After shopping for three days at various stores, I'm so glad I went with the Ashley's Elite 10" Firm mattress.  I was skeptical at first to buy a mattress in a box, but it lived up to its claim.  I've slept on it for a week now and find it to be firm and comfortable as claimed.  Best of all, you can't beat the price for a quality product.  My only regret is not getting the medium firm, but hopefully it will soften up some with use.