Thanks for that link. I'm taking a look at it but it relives the frustrations I've had looking for a new mattress. I have back pain but prefer a softer mattress, meaning I need to be somewhat uncomfortable in my mattress.
I just want a comfortable, durable memory foam mattress that relieves the back pain. Oh yeah, and for cheap! Do yall think these ~$300 queen memory foam mattresses that pop up on slickdeals will do that? They almost always have 3lb foam density which research suggests is not that great. But this site seems to be ok with it. Ahhh confusing!
If you have back pain, it might be because you're sleeping on a mattress that's too soft. I've always slept on a soft mattress and always woke up with a back that needed a lot of cracking and stretching. One night I stayed at a friends and slept on his crappy spare bed which was pretty firm and I woke up feeling like a champ. I couldn't believe how good my back felt.
Read over this section, maybe it'll help convince you to try out a firmer mattress.
One thing I've read is that if you can't slide your hand under your lower back while you're laying on your back, then the mattress is too soft and your back isn't getting the support it needs.