It’s comfortable so far; I’ve been sleeping markedly better on a firmer mattress. We’ll see how it holds up over time (I’ve only had it a couple of weeks). It holds heat, but not nearly as badly as other foam mattresses I’ve had. I’m optimistic that my summer nights will be a more comfortable temp than previous years. Besides holding heat (albeit just a little), my one complaint is that it is too long for my regular queen sized box spring. I read that this was the case in other reviews, but it’s still more than I expected.  It extends over the foot of the bed by about 6”. Not a deal breaker, but it limits my options as far as bed frames.