This was recommended to my be a professional photographer friend who flies all over the place with lots of equipment. I then researched what equipment carts were available on the market, and chose to go with this brand and this model. So far it's worked out fine.

This one, with the large back wheels is definitely the one to get. I've found that the smaller, front wheels are often too small -- but at least they're not dinky like on so many other carts.

I've had this extended to it's full size and piled high with equipment -- though only a couple hundred pounds worth, nowhere near the rated 500 pounds. It turns out that getting the smaller, front wheels over obstacles and rough terrain is problematic once you get more than, say, 100 pounds on it. But the back wheels do fine. I also worried that I might bend the handle by using it to drag a 200 pound load down a gravel path and over stepping stones and low curbs, so I treated it gingerly, and often had a helper push on the back handle while I was pulling the front. Maybe I was being overly cautious, but on the way to gigs I take no chances.

I also like that it folds up into a reasonably small and easy-to-store form.

In generally I'm pretty happy with it. I only need it a dozen times a year, so am hoping for many years of reliable service.

This is a valuable tool, but the load capacity is over rated, and the customer service response to problems caused by overloading is poor. I've put under 300 lbs on mine, and have experienced a sag in the telescoping squarepipe causing heavy restriction when I try to expand or collapse it. I have to now violently yank the telescoping part out every time I need to expand it, and violently shove this thing back to the smaller configuration. I contacted the manufacturer about this problem, and they told me that this problem was caused by putting it on an airplane, not by overloading it. I know for a fact that overloading it was the problem because this problem did not exist when I loaded it at a cab, and it did exist before I checked it into luggage. But purely making mention of the airplane, triggered customer service to say it was the baggage handlers fault. I didn't care about this communication issue so much as I just wanted to get a replacement telescoping pipe part so that I could use it more easily again. They told me they don't sell the part separately, even though they do carry other parts that break under heavy load like the wheels. Those broke under load for me and a client of mine who I'd recommended the cart. I asked them if they knew of anybody bending this telescoping part back into shape, and they did know that people had found ways to bend these back. They said I could take it to a body shop which might be able to bend it, but it might cost as much as a new cart, so I might want to just buy a new cart. So they know there is a problem here, they know its not easy or cheap to repair, but they aren't admitting it's a problem, they aren't providing a solution to fix it, and they aren't changing their sales specs to reflect a more accurate representation of what the cart can actually handle. There might be a way for you to distribute weight across 2 shelving units and put most of it on the larger axle side, but you definitely can't put anywhere near 500lbs just anywhere on this cart. Not only will the telescoping squarepipe bend, but the wheels can and do fall apart all the time on the r8 from just a couple hundred pounds and 10-20 minutes of rolling around on hard and carpeted surfaces. If they sold replacement parts I'd give this 4 stars. If the customer service didn't insist I was wrong about my experiences I'd give this 3 stars. But customer service is an important part of any product, and it failed me here. The one other star that is lost from this product is that its a bit janky, and the tolerances are very loose. The whole construction is crude, and the way the shelves are designed, it's not eloquent to assemble or dis-assemble this thing. For creatives using this, neatness counts. We carry impressive gear on this and there are much more tastefully designed carts out there. They just don't fold down as well as this does. Its useful and unique but I would buy any other brand if there was something else out there.

Imagine finding 4 people at $20 an hour all standing in a circle trying to get the thing unfolded - ugh. So frustrating. There are pull lines that you have to step on & hold, and then you have to balance on one foot while opening or collapsing it. Then the handle is too low, so you have to bend over / squat when you're walking with the cart. Very hard on the back. I have different staff helping me load & unload everytime, and no one can never figure out how to unfold on their own the first time. So I wonder where they have disappeared to, find them off on the other side of the van 15 minutes gone by & they are still trying to figure out how to unfold the stupid thing. Then repeat the process when it's time to fold it back up. And no, my people are not idiots - it is just not intuitive. Then there is the heaviness - I worry that I or one of my staff will break a finger collapsing or opening it - it is very heavy duty, but also very heavy & unwieldy. If I can figure out how to get it back in the box it will go back.

I purchased the R6RT for hauling fairly lightweight but bulky gear from my car to an event site. I needed at least 42" cargo area length. I wheel primarily over paved surfaces, with only short segments of grass, with total trips up to 3/4 mile at a stretch.

This cart has been a lifesaver. With the help of a couple bungee cords to secure my sometimes unwieldy pile of gear, I can unload my midsize SUV in a single trip.

Pros:
Folds down small enough to actually fit into the vehicle without taking up too much of the space intended for all the stuff it's supposed to help haul.
Very easy to set up and break down in a couple seconds.
Navigates paved surfaces easily and does well on hard turf, but I'm not pushing the 500lb limit. I wouldn't try to navigate mud or sand.
Appears to be built well
The wheel brake is easy to use and has worked perfectly for me when loading/unloading on a slope.

Downsides:
The upright handles are not completely rigid, though they move very little when loaded and with the bungees attached, and this hasn't been a problem for my use
The wheels on this model are pretty narrow and small. It'd be really nice to be able to upgrade the wheels without doubling (or more) the price of the cart by going to some of the other models. They work well enough.
The cart itself is narrow. This is great for passing through doors, not so great for stability. Be careful on lateral slopes with a tall load to avoid capsizing.

Additional note: One of the rear wheel bearings in my cart came missing 3 rollers. The Rock N Roller customer service was very easy to reach and had a replacement bearing at my door immediately. Huge kudos for their excellent product support.

R12 SUMMARY OVERVIEW: 3 stars. Add my voice to that of the Amazon reviewer who noted that s/he is "baffled by the enthusiasm" of the aggregate Amazon reviews for this cart. This wobbly, noisy, and unstable cart is undeniably handy -- especially on uneven terrain. Unfortunately, four fatal flaws undermine the cart's durability and ease-of-use, as follows:

(1) The cart's frame, front wheels and casters, and handle/pushing mechanism are very unstable, as are the attachments for the "optional" deck and shelf (see #4 below);

(2) The cart ships with incomplete assembly and reconfiguration instructions.

(3) The cart ships with parts that are vital for its assembly and operation missing from the product box, despite the assembly manual's claim that these missing parts are "included" in the box.

(4) The aforementioned "optional" shelf (RocknRoller RSH10 Carpeted Shelf for R8RT R10RT R12RT Models) and deck (RocknRoller RSD10 Solid Deck for R8RT R10RT R12RT Models) attachments -- which are themselves pretty wobbly, as several Amazon reviewers have noted -- are less "'optional" than they are necessities that give the cart's frame at least a measure of sorely-needed stability. (This is especially true of the RocknRoller RSH10 Carpeted Shelf for R8RT R10RT R12RT Models, which is pretty much a must-have to lend some stability to the cart's frame.)

PLUSES & MINUSES:

PLUSES: Even with its shortcomings, this cart is so handy that it enabled me -- a 45 year-old woman who assembled the cart by myself after consulting YouTube and the rock-star clerks at my local hardware store -- to complete a local move alone and on foot, moving 40+ boxes from my office to my storage locker one mile away without renting a car/van or enlisting movers, friends, or colleagues. (Tiger Balm and Ben-Gay are my gods!)

MINUSES: That the cart comes with such woefully incomplete assembly instructions and such significant missing parts -- e.g. yes, the phantom bolt that many Amazon reviewers of the R12 have reported missing really *is* AWOL -- is what made the aforementioned trips to YouTube and my local hardware store necessary.

Meanwhile, the aforementioned stability issues often halted or slowed my move, and certainly made portions of the move more physically demanding than they needed to be. (e.g. I often found myself coveting the "tricked-out" handlebars that several cart owners have added to their own R12s, per their YouTube videos!)

Finally, I agree with many reviewers who've noted that the process of attaching the aforementioned shelf is so involved and time-consuming that one feels reluctant to remove the shelf if one knows that one is going to use the cart again the next day -- even though leaving the shelf attached means that one can't fold the cart into its smallest, most space-saving configuration for overnight storage. When I saw other Amazon reviewers mention this, I thought it a churlish and petty point -- until I realized what a PITA this seemingly minor annoyance can become when one is completing a tiring, multi-day move and has a limited amount of space in which to stash the cart at the end of each day's work.

IMHO, FINAL ASSESSMENT:

Call me demanding, but when I pay $350+ for a cart and its deck and shelf attachments, I don't expect to have to channel Miss Marple and MacGyver to track down the instructions and "included" parts necessary to assemble said cart.

Moreover, when the cart's manufacturers have enough awareness of the aforesaid problems to deem it necessary to set up their own YouTube channel offering "essential" video assembly tutorials, advice, and shout-outs to cart buyers who have posted their own YouTube video workarounds and "trick-outs," I gotta ask myself: "Why haven't the manufacturers simply redressed these known issues by: (1) recalling shipping lots that they know are missing required parts and (2) e-mailing cart buyers a PDF attachment containing complete instructions and links to the manufacturer's YouTube tutorials?"

That said, the R12 really is very handy -- especially for an independent gal like me who'd rather get a multi-day road workout than employ movers or hit up friends and colleagues for help with a relatively small move. Having put the cart to good use during the aforementioned office move, I don't regret purchasing the cart and plan to hold onto it. However, I remain disappointed about the issues described above -- especially since each of these issues seriously detracts from the cart's ease-of-use, yet would be quite easy for the makers of the cart to redress.