PS+ is a great deal. When I first bought it I went on the PS forums bitching about how lame it is. Months later I think it is one of the best subscription values you will ever see in gaming, period. I can understand why someone might not think it is very good but I would also have to question how much, if at all, they have really used it.
After months of use I can tell you I have saved enough on PSN games to pay for the service, in addition to all the free games they give you. Yeah you will lose them if you forget to re-up your service but it has autopay setup so that really is no excuse at all. Anyone who tells you something is wrong with this service either only had it on trial, had no disposable income to really use it properly, or is a closet Xbox fanbaby.