I love them personally. As others have said, I like that I don't have to dig around for a FP, Photopass card, park tickets, room key, or my credit card. It doesn't save me from having to carry anything (I always keep my ID, credit card, and some cash on me), but I have to carry a bag anyway due to the medications I take. So either way I would have a bag. But when I go refill the mugs for myself and those staying with me, it is a LOT easier to use my MB to open the door then fumble with a room key card!
The only thing I wish they would figure out is how to allow parties to set up different credit cards for charging for different bands. As of now, you have to stop by the front desk to do this.
As for FP+... I really like it, especially as I start to have mobility issues. These days I would be unable to keep up with the pack to get that first FP and would be in the back of that line wasting valuable park time. Plus, if I want to ride something before lunch (to reduce the possibility of getting sick) or at night (for a different experience) then I can make that happen where before I would either have to wait in the standby line or hope for the best.