I think we like the regular DDP the best. I think it's only $10 more/day for 3 of you and it opens you up to all the character meals and some great buffets. We're really not into the Deluxe Dining plan as it would be just too much for our family to do 2-3 sit-down meals/day...plus it's waaaay more per person. You also are getting close to June as far as ADRs are concerned, so trying to do the Deluxe plan at this point, would be harder because you'd need to secure 2-3x as many adrs than the regular plan.
That being said - my hubby and I only tried the dining plan for the first time this last visit. In the past, we've had family with us part of the trip, and some who didn't want the plan, so this was our first trip that it would just be us to be able to use it. We loved it.
We used it for 7 nights, so we had 7 TS credits. The kids, hubby, and I all used 5 of those 7 with meals together. Then one night, we had the kids being "sitted" and hubby and I treated ourselves to Flying Fish (2 credits each).
For character meals - I'd suggest Chef Mickey's and Donald's Breakfast at AK and maybe Ohana. Crystal Palace is good, but I'm not sure your sons would like Winnie the Pooh and friends??