Background:
Let me start by stating I have never used a roto-tiller before so I do not have anything to compare it to. I purchased this item because I needed to reseed a 50 x 50 area of my lawn that had been taken over by crabgrass. After working a short time with a rake I decided to purchase a roto-tiller to do the job. I typically am one that likes gas operated equipment and high end equipment. however being that I was only going to use it infrequently I felt a gas operated tiller may not be best because of long term non-use. After reading reviews of several I decided to purchase this unit.
Review:
First, because of the current rating (12 amps) I purchased a 12/3 extension cord with unit. Most extension cords will not handle the current for this device. I would highly recommend you do same. The unit comes in 3 pieces and assembles quickly. The weight of unit is manageable and should not present issue with most users. To start with I would like to say I was quite impressed. Although my yard is not very rocky it made short work of cutting thru the weeds and hard packed soil. I started with the adjustment at the greatest depth and quickly realized it was to much. The unit easily dug a hole and buried itself. After readjustment I found a setting that dug a depth to about 4 to 6 inches. The unit was very manageable at this depth. Deeper depths require more effort to get thru the "mounded" soil it creates. When the unit did encounter rocks it easily pulled it them out. Several where in the 4"-5" range. I would estimate that it took about 45 to 60 minutes to do the 50' x 50' area. I did not work continuously, I stopped on occasion to allow the unit to cool and rake to the area previously done. I allowed the unit to cool only because of others comments that they "burnt" out there unit. Quite honestly I think it would have been fine to do this entire area without stopping. However I should note that long weeds/grass do wrap around the shaft. You should clear them occasional (see attached video) to keep them from cutting into the transmission seal and/or binding the unit up. I suspect this may have been the cause of the previously mentioned reports of units burning up. I would also add others suggested using hose clamps at the handle connections to make the unit more rigid. I tightened my handles with a wrench and found this not to be necessary. I gave it five stars not to indicate its the best tiller ever just that it performed at or better than expected/advertised.

With just a few hours in the garden, I'm happy enough with this tiller to give it four stars. With very rocky soil in Utah, the Sun Joe pulled out just about anything fist sized or smaller. The only trouble I had was when it ran into a chunk of soft brick. It jammed in the tines. A couple of knocks with a hammer dislodged it and the machine went on running. (See photos. It pulled up a lot of rocks.)

So, why not five stars? I'm comparing it to other tillers I've owned in the past. I found other machines easier to keep in position to dig downward. However, those were far more pricey. (And of course, there are all the little annoyances that come with a long power cord -- no more than minor annoyances as long as you keep the cord in the clear.)

TIPS: When using the tiller, try lifting the handles (forward) and you'll likely find it easier to maneuver and that it will dig in a bit better.

I bought this 2 years ago and I have beaten the he** out of it. I have rototilled my entire front yard, which is heavy clay and rocks. I used it to wear down a hill. I have tilled my flower areas about 20 times each. Is it as good as the gas powered one I used to rent? Nope. But that's $40 for four hours. I've used this probably 200 hours, so it's paid for itself many times over. Finally, this year one of the cultivating wheelie thingies broke off. Don't care. Still works with 3. It's light and easy to maneuver, relatively quiet (for a rototiller), and if you are patient and have a good grip you can till down 3 or 4 inches even in bad dirt. Bottom line: When this thing finally dies, I'll get another one, cuz one of these days I'm going to try to grind down a stump with it just to see what happens.

I live in upstate New York, so my flower beds are a mixture of rock and clay with the stray handful of dirt mixed in for good measure. I have been putting off planting vegetables and flowers because of the pain of digging out the rocks and preparing the beds. Although I read rave reviews of this Sun Joe tiller and its smaller brother, I was worried that the fist- and foot-sized rocks in my garden would jam the tines and burn out the motor.

I am happy to report that the tiller handles rocks and clay like a champ! Yes, when the tiller hits a good-sized rock, it will buck and skitter, but more often than not, it will then pull it out. Like others, I found the most effective approach was slowly pulling the tiller backwards through the bed. I wore safety glasses as a precaution, but the tiller spits the rocks out in the forward direction. My work flow was to make a backwards pass down a swath of garden, then stop and pick up all of the spit out rocks. After preparing two beds of ~8' x 3', I had extracted enough rocks to full a 1 gallon pail twice over. I then used the tiller to mix a healthy dose of peat moss into the dirt and clay.

The tiller blades became jammed on large rocks twice. The first time, I was able to bang the rock out of the tines. The second was somewhat larger and will require me to remove the tines. This looks pretty straightforward; however, it happened just as I was finishing up, so that is a project for another day.

In summary, I am very impressed by this little tool! There is no way I am going back to my old method of digging out rocks with a shovel.

Just to be clear I got mine at HOME DEPOT and it IS NOT a 12 amp model. Mine is the 13.5 amp model and it was $159.99. It is exactly the same with just 1.5 amps more. This thing is super powerful. I have tilled about 1/3 of my yard with it so far and it has performed very well. It does feel a little rickety out of the box so I installed four hose clamps, one at each screw. Let me tell you the hose clamps make a HUGE difference in the performance of this machine. If you are tilling hard clay earth like I did, you will need to manhandle it a bit. I'm 25 and 180lbs and it made me tired, my hands hurt and I was sore the next day. So if you're not tilling soft (wet/damp) earth be prepared for a workout. If rained today and I tilled some, it just gobbles the dirt up and spits out huge rocks no problem, see pictures. Again I urge you to get a four pack of hose clamps if you buy this machine, it makes it just sooooo much more sturdy. See my pictures.