I can't speak for dining plans that are full price during the high season - I suspect that those conditions may alter my decision. We almost always go during the autumn and when FD is offered. We always upgrade to DxDP and it works for us both in trip satisfaction and financially. I won't bore you with our exact numbers but we review the menus for what we'd like and then add that cost up - compare that to our upgrade costs and it has never not been more savvy for us to go DxDP.
Some of the things that make it work for us are:
1. I don't generally like CS meals - I feel that they are too much like fast food and the cost for that fare gives me sticker shock. On vacation, I prefer to dine with a table service experience and I'm okay with paying more for it.
2. We don't lose any park/ride time but we go during the off season so I suspect that makes a huge difference for us. In fact, we love being able to take a break and enjoy a leisurely, relaxed meal. We find lingering over a meal inside actually recharges us for more park time! Never had an issue with losing out on a ride or a show. Again, I suspect that the time of year is a huge factor here. We also plan as many of our ADR's to coincide with the park that we are touring that day. We rarely have to leave the park and if we do, it's almost always for dinner after a full park day.
3. We really love character dining and plan one every single morning - always getting ADR's for BRD. We really like getting into the parks early and eating so very early means that we are ready for a meal at lunch.
4. Don't quite get the too much food issue.

We super space out our meals - breakfast at 8 AM, lunch at 1 PM and dinner at the latest ADR available. We don't overload at character breakfast buffets because we know we have other meals later. We are starving by lunch from all that exertion! We also have a son who is a foodie at an early age and turns his nose up at the kiddie menu. We order him the most palatable item from the kiddie menu and then share bits of our meals with him. We each order a different appetizer and dessert and everyone takes bites of each others. It's a great way to try new foods without worry - if you don't like what you ordered, you aren't going to go hungry. Some trips we don't use all of our snack credits and cash them out at the end. Some trips the weather is so hot that we use the credits for drinks mostly.
One small note about a non-budegt difference between
DDP and DxDP: I prefer DxDP because I enjoy the flexibility of choosing TS/CS, signature or not, appetizer and/or dessert selection and 2 snack credits. I don't always use them the same way but it's much more fun to make dining part of your park experience when you have DxDP; there's simply more unrestricted credits to play around with!
You have to plan what works for you and for that particular trip. I think factors are how hard you play during the day, amount of time spent between meals, time of year you visit and eating habits of your family all come to play.
One thing not mentioned enough is how your family views dining as part of your vacation. We enjoy eating out and feel it is part of the whole experience so we don't mind planning for it much as you plan to see a parade, show or special ride. It's part of the fun of Disney to us so we savor a leisurely meal in a unique environment. I know that not everyone feels that way - to some, dining on vacation is just fueling themselves for more Disney fun! They want a good quality meal that doesn't cost a fortune and gets them back in the park quickly. Nothing wrong with either approach - but it's something to consider when deciding on a DDP or a DxDP.