I have never spent 2 hours at a TS restaurant except for Ohana. Our meals generally take us an hour or so, sometimes less (and yes, take care of that check early on!) We do character meals every morning, enjoy a relaxing air conditioned sit-down lunch around 1pm and another relaxing meal in the evening. Because our breakfasts are before the park opens we don't lose any more time than those that do one 1 credit meal & a signature meals to take up 2 of their credits, and I imagine signature dining takes a bit longer (atleast that is what my MIL experienced when she had a signature meal and we did a regular TS meal the same day/time). We also dine in the park we go to that day (or nearby resort) so we don't lose any time traveling from place to place.
It is a lot of food, but the only meal that we feel full from is dinner. Breakfast is used as good fuel for getting to those rides hot and heavy in the morning. Lunch provides a much needed break in the early afternoon and refuels us for the rest of our day until dinner comes around. With park hours and such, we don't have 5 hours to go run around and burn off dinner like we can breakfast and lunch.
We have two girls (4/8 on our next trip in May) and they are accustomed to eating 3 meals a day and have been eating out in restaurants most of their lives so the deluxe plan works great for us. It may not be for everyone, but I wouldn't let others discourage you either. If you plan it right, it's great!
Definitely take care of your check early at character meals (any meal really) especially if you are trying to make rope drop in the morning. It can take quite a while to finish with the many receipts they bring you when you are on a dining plan. Plus, you are taking care of it early when most wait till the end of a meal, which makes everything take longer because everyone is doing the same thing. We learned the hard way at Crystal Palace. We had finished eating and meeting characters by 845am - yeah rope drop! Nope, it took over 15 minutes to take care of the check.
We met over 40 different characters on our last trip (went through 3 autograph books) because we were able to meet so many characters at our character meals and did not have to wait in line for them unless we just wanted to. It was great!! Financially, the deluxe plan makes sense for us because we do so many character meals and they are quite expensive.
Enjoy your trip!