I had a very nice day at DCA this past June. I have been to WDW several times and I thought DCA was far superior to MGM. MGM has just a small handful of attractions (rides) and some of them are not suitable for little kids. I call MGM the 1/2 day park. At least at DCA, we had plenty to see and do all day. And really, who can be disappointed when your day ends with the MSEP.
I liked DCA because it felt relaxed, it was easy to navigate, I never felt disoriented about where I was in the park. It's not overtly DISNEY, but after spending two days over at DL, I was ready for another vibe. One of my favorite aspects of DCA was the music that was piped in. How can anyone have a bad day listening to the Beach Boys, The Mamas and the Papas, The Turtles, etc.???
All my interactions with castmembers were pleasant. Actually, we are heading to WDW in November, and the other day, my daugther said, Mom, when can we go back to DLR? She and I both prefer DLR's Magic Kingdom to WDW's Magic Kingdom.
It's a no brainer for either of us... We love DLR and DCA is tops too!