It's totally up to you and your vacation preferences. Only you know how your party prefers to eat in general, and what importance dining is on a vacation.
Personally, I'm not a fan of quick service much at all (there are some locations that serve food that I like, I just don't like the whole experience), so I'm biased, but I couldn't even imagine going for 14 days on quick service only.
On the other hand, if you're not a big fan of table service, using 14 TS credits over the course of two weeks could be tough.
The cost difference is $11/adult/night and I believe there is no difference in child costs. Do
you think trading a snack for a table service meal is worth $11/night for adults?
Another option, and granted, this requires an extra ticket purchase, is to consider a "split stay", where you book separate consecutive packages, each with a different dining plan option. For example, spend 7 nights with QSDP, and 7 with
DDP. This would allow you to do some table service (although grouped closer together) without having to do it for a full two weeks.
Then there's always the possibility of just staying on QSDP and adding a few TS meal out-of-pocket, if you only want a few.