Hi, Ashley! There are advantages to both the dining plan and the Tables in Wonderland card, depending on your family and your dining habits.
Disney Mom Deborah gives a great answer to some of the exclusions on the Disney Dining Plan in her answer located
HERE. In addition, there may be a rare menu item exclusion, but those are few and far between.
The biggest advantage to Tables in Wonderland is that it discounts your entire meal, alcohol included, no matter what you order. There are no menu restrictions, and you don't have to order a minimum amount of food to use your TIW card. That means if you want to hit a participating restaurant for just dessert, you'll get your 20% discount, or if you want to go for dinner, but you don't want a dessert, you don't have to worry about leaving an included part of your meal.
The best reason for the Disney Dining Plan is to help you budget the amount of money you'll need to cover meals. With it all paid for in advance, it's one less vacation worry! You do get a lot of food on most of the plan options, including the quick service plan. My family has various eating issues, and there's no way I could eat the amount of food on the dining plan, but if you have a family of healthy eaters, or if you like to splurge on vacation, you will certainly get a full meal with the dining plan, without worrying about busting the budget by ordering that ice cream sundae! The dining plan also gives you at least one snack credit (depending on the plan), so you can grab a popcorn or Mickey ice cream bar when you want.
I hope this helps you make your decision!