If anyone is in the market for a new mattress, here is my take on the Purple. I love it! I won't lie, I slept like crap for the first week, but it wasn't because I was sore anymore. My joints felt great, but something about it being a new mattress didn't let me get a good night's sleep. As of today, I am sleeping like a rock and my back and hips are feeling much better. I will say that it is VERY firm. I may be big enough that it doesn't bother me when I sleep on my side. My wife weighs 115, and she is a stomach sleeper thank god, because she says it isn't very comfortable to be on her side. It seems to be temperature neutral. I don't feel like it makes me hot, but my wife enjoyed the old mattress providing some heat, so now we have an electric blanket....
Overall I think it was a good investment. If you like a firm mattress and sleep on your back, I think this would be a good fit for you.