Hello,
Like above, we used this for the first time in August. We loved it! We researched restaurants and pre booked all of our T/S credits. We used snack credits for gifts home too (I believe you can spend upto $4) - we bought drinks as it worked out better value this way. We were left with 1 C/S on our last day, so on the way to the airport Mid afternoon, we stopped off in DTD and bought goodies from The Earl Of Sandwich to eat at the airport.
It's dead easy to use and keep track of what you've used and what's left. Any member of your party can "pay" for your meal as you all have the party's credits on your cards.
Do your research on the restaurants, make ADR asap and if you are wanting to meet the characters,book as many varied character meals asap, this saves times in Queues in the park!