Mattress Forum

I'm currently shopping for a new mattress.  I want to keep the price low, but I'm willing to spend up to $600.  I found a mattress at a mattress firm, the Serta Apple Valley memory foam.  I am having trouble finding reviews on it.  Does anyone have any input on this mattress?  I found it for $399, but I don't want to spend the money, only to have it lose shape on me after a few months.  

If anyone has better suggestions for firm memory foam or gel mattresses that are within my price range, I'm sitll open to suggestions!  I can buy it online just as easily....I was looking at overstock and stuff, and they seemed to have good prices, but not having laid on the mattresses before purchasing worries me a bit.

Thanks for the help!