I was about to purchase a Stearns and Foster bed until I went on the Internet today and saw an overwhelming number of reviews that state the bed gets saggy and lumpy after about a year. Anyone have any idea if that is specific to the pillowtop, or does the entire mattress fail? Am I safe buying without a pillowtop and adding my own cushioning later? If their beds are junk, then what inner-spring mattress companies have good reputations these days? Also, are all built in pillow/euro tops looked at as a bad investment? Thanks.