We recently went to Disney and stayed on property along with doing the dining package for the first time. While I still like staying off property and renting a house for more privacy if you are only doing Disney parks for a short portion of your stay, being on Disney property when the entire trip that was the only thing you had plannned for the length of your stay was very much worth it. Having the dining package which meant only having to pay for tips at sit down meals was such a nice change and much simpler than always carrying cash or credit card. All you need is your room key and everything can be charged to the room.
Food quality, while completely subjective, I felt was very good to good just depending on what we ordered. Sometimes we ordered well, others not so much. In hindsight, we ate dinner at the Rainforest cafe one night when we visited Downtown Disney. In hindsight, we would have preferred to do another character dining. Food was great but I would have liked to see the characters. Also, the quick dine meals, kids don't have to choose a kids meal even though they are available. Some places the kids choices made no sense. At the pool restaurant at the Grand Floridian for example. The kids choice was a chicken wrap with cabbage and veggies but on the regular menu there were chicken fingers. We just swapped meals since this was before we realized the kids could order any meal for their quick dining choice, not just a kids selection.
Overall there is so much value in the dining plan, especially when they run specials on it. I highly recommend it.