I'm in search of a new mattress and I found a good deal on the Serta Gel Foam bed at Sams Club so I'm considering it, but my husband said he's heard that they get very hot. Anyone experience sleeping on these beds? What's the verdict? Are they comfortable or are they hot? I thought it was just the memory foam beds that get hot. My husband and I both have back problems so if you can recommend a decent bed that's good for back problems (but doesn't cost too much) then we'd appreciate any recommendations. We're looking to spend no more than $550 for a queen set. I know, tight budget