I bought a foam mattress on Woot at one point. At first, I loved it. Best sleep I'd had in a long time.

After about a year or 2, I started to notice that I was not getting good sleep and my back was achy a lot.

I got a new bed with a more conventional mattress, and I was a lot happier with my sleep again.

The old mattress? I gave it to my mother. "Best sleep" situation for her again, but after a while she replaced it.

I think initially the comfort is amazing, but either it slowly erodes your back's health, or you slowly learn to sleep differently on it, and it hurts your back. At least, that's how it seemed for us.

Totally unscientific, but that was my experience.