I read the reviews and thought that since there were more 4 or 5 stars I would believe them - so I purchased this mattress. Now this is a lot better than the (very) old spring mattress that I had, BUT it is barely 4.5 inches and you can definitely feel the bars underneath. We ended up putting a piece of plywood under to remedy that. It also hinders me from folding up the couch easily - maybe that will lessen with time. All in all everyone that has slept on it has said that it was "ok".  

Cons: Can still feel the bars