We used QSDP for the first time last year and I loved it! No more planning ADRs months in advance and then having to chagne them when there and our plans changed (we aren't overplanners on park schedules).
We had great food at most places. We do have a car so going to DTD to eat at WPE. EoS, or Cooke's was pretty easy. We had more food than we needed, though we managed to use all of our credits (okay, I did treat a nice couple at EoS to their meals on our last day) and the refillable mugs are a nice souvenir (we would buy them anyway) even if you don't like Coke products (though it would be hard for me if WDW switched to Pepsi since I'm a Diet Coke girl all the way!

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Luckily for us we only paid for the
DDP one time, back in Jan. 05 when it first started. Since then we have had it for free. If I had to pay for it I would look at what I would normally spend for meals/snacks and see if it was worth it. Right now, with QSDP inc. 2 snacks a day I still think it's a pretty good deal, pretty good, not great.
As a PP mentioned though, one of the things I LOVE LOVE LOVE about having a DDP is that I don't have to worry about the cost of things. If my DD11 wants a snack I can tell her yes without worrying about the cost. She loves this as well. And even with that option we have snack credits left over to use on our last day for brining home stuff. (Maybe that's why they are eliminating one snack per day?)
And last but not least, using SC at the F&WF. A no brainer! We had such a good time being able to get whatever food we wanted last year (our frist F&WF) that we wanted to make sure we made it back this year so we could do it again-and we are!
Quick question-are your sure you can't get free QSDP? Based on your ticker it looks like you are getting there on Oct. 8th. If so that happens to be the last day for checking in to get free DDP. We are actually arriving on the 8th for our free QSDP trip. I jstu booked it this week when they opened up more dates. Or is it that your Cruise part is first and you'll be checking in after the 8th?