At first I was a little worried that it came in rolled. It was a big box mind you... it was a box of about 18x18x60. To my surprise it laid out flat! perfectly flat! I guess it really doesn't bend permanently.I'm about 200+ lbs and there are no depressions from the wheels. I put it on a 0.5" carpet and this thing is TOUGH! Worth the money I paid for it! Because if you shop around, you know low quality standard-size mats are around $50, and the medium quality ones are about $100. Well this one is super high quality and easily 4 times BIGGER than the standard sizes. Paid $150 for this. Worth every penny! Love it love it love it!Highly recommended! Spend the money! Don't waste your money on a mat that YOU KNOW you will be unhappy with anyway. Spend the extra money! the standard size for this mat is $120. Don't get the vinyl ones, those are the ones that crack, bend and smell. spend the extra $20-40 and get a good strong mat that will last for years!The secret keyword to search for is: Polycarbonate. That's the stuff this thing is made out of. And if you read the reviews, everybody agrees these are the best kinds of mats!EDIT: 2 months later. This thing shows no signs of wear or depressions. It did roll around a lot at first, I put the super smooth side on the carpet that's why. I like having the rough patterned side to step on. I finally caved and drilled a hole on the corner and screwed the thing with 2 L brackets on the very corner of the room. Now it doesn't move anymore. problem solved!UPDATE 11/07/13:So haha I have purchased all sorts of sizes of this polycarbonate material. I use it for my home business and all my chairs have this, as well as some surface table where I needed a smooth surface that could slide stuff easily. So I purchased about 8 of these already in different sizes.This big one that I bought is still very much intact and well no depressions or dents, as in zero depressions. My only thing is DON'T run your chair wheels on the edge of the mat too often. I placed my mat not close enough to my desk, and everytime I rolled to get closer to the desk, the wheels would stress out the edge of the mat. It's basically like plyboard--you can bend it but if you fold it too far it's gonna snap and crack. What I did was I bought another mat and put it under to extend it and to stop the crack from becoming a big problem. Or you could just move the mat so your chair is in the center of the mat not on the edge. Mine was so huge that there's furniture that helped hold the mat down, so I didn't bother moving it, I just bought another mat to extend it.Also I agree with the other review that if you put it on a carpet floor and you step on the edge it has a tendency of rising up a little bit. I ended up rounding the edge because the edge is a square point--and altho it won't really cut you, it will hurt if your other foot/toe gets caught lol. Another helpful way is to get those carpet holders that you put under rugs so the rugs won't move. Haha I did that on a couple of ones that kept moving and it's stuck now, it never moves.