Summary: I purchased this for a bathroom remodel, installation went smoothly, and I'm very happy with the result. My wife's cold toes are even happier with it!

More detail: This is the first time I've installed a heat mat of any sort, and in fact the first time I've tiled a whole room on my own. Despite my beginner status, the whole process went smoothly. I did all the wiring first (power to the heat mat, thermostat control to sensor), then installed cement backer board. I put this heat mat directly on the backer board, using plenty of staples on the mesh part (not over wires) to hold it in place. (If you have an air compressor, I highly recommend a Surebonder 9600A, Heavy Duty Staple Gun with Case any time you do a lot of stapling. Much faster and less tiring.) You have to know the exact size and location of all your bathroom fixtures at this point, so the mat doesn't extend underneath anything permanent. Don't forget to place the thermostat sensor on the floor between wires at this stage also. I cut a little gouge in the backer board, so the end of the thermostat sensor wouldn't stick up so far. After I got all the tiles cut, I put thinset over the top of the mat. This is a little tricky, because you want a thin layer of thinset on top of the mat itself, being careful not to gouge the heat wires with your trowel, and then you want a thicker layer outside the heat mat, so the tile ends up level. Just be aware of it, and make sure you have plenty of thinset on hand. I didn't have any problems using a metal trowel over the heat mat; just be gentle and don't scrape through the wire. It's also tricky to apply thinset & place tiles after the heat mat is in place, because you need to be very gentle walking/kneeling on the heat mat. Then finish tiling as you normally would.
I have not used this through a whole winter yet, but we've had several chilly fall days and it has worked wonderfully. As with most complex timer thermostats, he thermostat programming is not especially intuitive, so keep the instruction manual handy. But the instructions are clear, and once you get it set up it works well with the various automatic / timer modes.
Overall, I have no complaints about this product, and it was the best deal I could find if you also intend to buy an auto/timer thermostat.

This worked perfect for me in my smaller bathroom. I ordered the 25 sqft size. I have a few observations:
1. Order the exact size you need, and go short if anything. If you order 25 sq ft but needed 21 sq ft (my case), then you must run the extra wire around your floor. You cannot cut off the excess wire.
2. Install wire side up, or matting side up? All of the wiring must be must be embedded in thinset mortar to conduct efficiently onto your tile, or whatever flooring you're using. I laid it mat side down, and wire side up because of this. If you lay the wire side down, then you would be smart to lay down thinset first, then the wire side down mat, then thinset over the top. IMHO, and with my electrical engineering background, this seemed like unnecessary work.I used a staple gun to secure the mat to the floor. For places where you have wire without the mat, I would not use staples. The metal is conductive and corrosive, but you also run the risk of damaging the wire. I just bent it into place without securing it, but you could use a glue gun or something along those lines.
3. Hide the transition of heating wire to electrical wire within your flooring. There's a fat little transition that's a good 1/4" thick and maybe 1" long, that needs to be embedded in the floor. Do can't stick that part behind your baseboard moulding because it's attached to the hot wire on one end, which should be spaced at least 2" from your baseboards. I used a dremmel tool cut out part of my plywood flooring to make sure the tile lays flat in that area.
4. Don't forget the temp sensor! I almost did. You space evenly between two parts of the heating wire.
5. The thermostat provided requires a neutral wire from your house. If you're house was built before the 80's in the US, then you need a different thermostat. Or you would need to run a new set of wires all the way to your to your electrical box to get a neutral. Do not use the ground as a neutral; you run the risk of causing a fire down the line.

Comments: Mine works flawlessly, and I love it. I highly recommend it.

Every morning I go into my new bathroom I think: "NICE"! And it is indeed! This is also a very good value - you get the mat, the sensor, and the thermostat.

I installed this mat in my basement bathroom directly on the cement slab. Before installation measure the resistance and make sure it is within the range specified on the wire tag. Also, measure the sensor resistance and also make sure it is working properly. I installed one extra sensor Honeywell AC112-01 Electric Heat Floor Sensor just in case the first one dies out (imagine installing everything and having no heat because of a busted sensor).

It is fairly easy to lay it down, and to cut the netting (not the red wire!) and arrange on the floor. However, the wire tends to lift at every corner when changing the direction. If you have wood subfloor you can staple the net, but in my case I was able to make it stay flat brushing it under and then over with the primer for the self-leveling concrete (my floor was very uneven). I put about 1/2" of self-leveling over, then I placed the sensor under the tile (not with the mat) as I wanted the temperature reading to be more realistic. It takes less than 30 minutes to get from 68F to 76F.

They specify that you need conduit, so I had some old 12/3 wire with metallic jacket, I pulled the wires out and used the conduit from the floor (through the stud) to the connection box. From the connection box to the thermostat I used regular 14/2 wire (this thing is drawing 3A, uses 360Watt and it requires a GFCI breaker).

The thermostat is not the best - you can program 4 different time periods per day but only 2 temperature setting (?!?!). Night time, with day time share the same temperature, as do morning and evening (you can use only 2 periods if needed: day and night). What if I am home the whole day and want some heat but not as low as during the night? What if I want a different temperature in the evening vs the morning? Tough luck. Well, this is the thermostat issue, not a heat mat issue, so I don't want to deduct any stars here even though I feel compelled to...

I have it at 76 in the morning and evening, and I have an infrared thermometer and it is spot on. The thermostat cycles on and off pretty quietly, and not too often.

I purchased the 30ft mat, but in all honesty the 20ft one would have been enough (only 240 watt). They mention that you should not install the mat too close to the wall or under fixtures anyway. When making the decision which one to get, think where your feet are touching the floor, and where would you actually appreciate the heat. For me it's too late to change now...

All in all I am very happy with it. Would I purchase it again? Definitely. But If I had just a tad more money, I would look into the Ditra Heat. Just saying...

I cannot yet comment on the actual unit because it hasn't been installed yet. Probably tomorrow or early next week. Our bathroom is freezing and never comfortable. What I can comment on is my purchasing and shipping experience. I had somewhat of a difficulty navigating the website because I didn't know exactly what to call a unit that heats a floor from underneath the actual tile
I found it once and it took my 2 two days to fond it again. Once ordered the unit did arrive in a timely manner and is undamaged, so once our new bathroom is finished I will definitely let everyone know how it worked out. The units range from $140 to $3,000. I paid$200. I hope it works out.

OK...so there is much to like about this thing and a few things that are puzzlements. .First, the good. It is installed and works wonderfully in our newly renovated tiny little master bath. The installation process is pretty straight forward, once you have the floor appropriately prepped. The first challenge is figuring out how to trim the fiberglass mat to allow it to fold, flip, and turn to cover the area you want heated, while leaving the lead wires at the best spot for feeding to your thermostat, but as noted by other reviewers, a little creative patterning will work it out. The next problem is when you skim-coat the same mat in preparation for the actual tiling, you have to understand that you are essentially going to be tiling an uneven floor because even if you mix the mortar extra runny, you will end up with two different heights. I addressed this with either normally buttered tile in the heated areas or I buttered the crap out of the tiles being laid on the unheated areas which were below the height of the skim-coated sections. Used a 2 x 4 with a three foot level to verify consistent floor/tile height and yeah, I did have to pull up a tile from time to time and slather on a bunch more mortar but this was not my first tiling job so I was not too concerned with the practical issues...Ended up looking great and worked fine. My biggest gripe is the thermostat. The instructions encourage you to place the t-stat outside the bathroom, which makes sense but I suspect that unless you are involved in totally new construction, rather then renovation of a single bath, the t-stat design will make you crazy because it is big enough to require a 4 x 4 Jbox but a single center decora plate. Ever try to find what is essentially a double gang plate with a single centered decora opening? Don't spend much time looking because you never will. You can find new work solutions but if, like me, you want to put the t-stat outside a renovated bathroom without getting into drywall repair, paint etc on the other side of the wall, then that's a problem. I finally found Kyle Switch Plates on the interweb, bought one that came close, then Dremeled out a large enough opening for the decora guts of the t-stat to fit. Looks kinda funky, as you can see, but all in all, I am happy with it. Warming Systems really should offer the exact solution...and btw, they might....I never bothered calling them! But even in spring, the heated floor is delightful and I will never live in a house without this feature again.