We've only done "free DDP"; would never pay for it. We are & always have been very wise with our money. Definitely not "cheap", just financially wise. We would never pay more for something just for convenience - a gift card would do that for us if we couldn't afford to wing it while on site.
One time when we were on Free DDP, DH got sick (flu I think) & we stayed in the room for 3 days. I was glad our dining plan was free because he didn't use it during those days & to stay with him, I only used it for bringing food to the room. We would have freaked out if we had paid for the dining plan!
One point not mentioned is illness or emergency that cuts the trip short. Disney will refund the resort pre-paid amounts (minus $200), but will they refund the dining plan portion?
Do most folks who pay for the dining plans have
travel insurance to cover the cost?
Also keep this in mind - we always add non-Disney days after our Disney resort stay. I tore a knee cartlidge during our trip last fall & the Disney insurance would not pay for our emergency & early flight home, because we weren't leaving from our Disney stay. Early flight total for the both of us was $375. However, we did get our $200 Disney cancellation fee refunded.
I think for those who aren't concerned about being wise with their travel money, and those who don't place risk or debts on their household for their trip to Disney, should go for it! Basically, it's for those who can afford it, not those on budget trips. But then, I don't think staying at a Disney resort is a budget trip anyway, even without the dining plans! It amazes us that we can easily go to Europe for the same price & we prefer travel variety, which includes some Disney. Again, if you can afford it & you like it - it's a no-brainer!