We have found our Serta queen mattress to be a very comfortable and affordable mattress. We both have back problems and need a firm mattress, but don't want to feel like we are sleeping on a board! The Serta is very comfortable, with just the right mix of firmness but also providing cushioning so we can rest and wake up feeling refreshed.
I do tend to get allergies and have some sensitivity to chemicals, so I sometimes wake up with a stuffy nose. It would be better with an allergy mattress cover and allergy pillow covers, but is otherwise a good mattress.