It was well worth it for us.
My DH stayed home so it was me, the crazed DisneyMOM

, and my two teen DSs.
We do one table service per day, usually for our dinner and we like high end dining experiences. Wolfgang Puck's at DDD, Le Cellier, the old style Cindy's for dinner, 1900 Park Faire (character breakfast), California Grill (2 TS), etc.
As for snacking, my DSs would grab an evening snack from Roaring Forks at the WL and head to the pool. And this was after a substantial dinner! They are fit kids with that incredible teen metabolism.
Snacks like frozen lemonades or cokes were a light treat in the afternoon or an occasional bottle of water.
Weigh your options and your dining preferences. We like to take the time to have a sit down dinner and be waited on. We would breakfast in the room, counter service at lunch, break for a swim in the afternoon and back to the parks or a resort for dinner.
Either way, you're going to Disney.
Enjoy!
--penny