TiW won't work at some non-Disney owned places like Landry's properties, Mitsukoshi places in Epcot, Planet Hollywood, etc. However, the AP 10% will! The only places TiW is really accepted where the AP discount is not are the value food courts since they do not have TS restaurants. It doesn't work on mugs though. We're not huge drinkers, but I can't pass up some drinks like a sunken treasure or lapu lapu so TiW helps there. We also enjoy HDDR and the Luau so it has helped to get 20% rather than 10% there! Sometimes I order custom cakes and ask for the price to be added to my reservation's bill just so I can save 2% haha
I can usually get 4 trips on one TiW card. Disney usually gives you it for 14/15 months and you can use discounted gift cards to buy it