So I am back for my trip and I used Ridemax in both DL and DCA.
For DL, it was perfect. In fact, we had a lot of extra time because the lines were so manageable. We were able to take in the "magic" of Disney.
DCA was another story altogether. We ant on an EE day and headed straight for RSR. We got in line and it should have been a 10 minute wait, but the ride was not up and running. They were still doing some testing and did not load passengers until close to 7:40. So, we ended up waiting for close to 50 minutes and did not get to ride anything else during the EE. By the time we got to the Fastpass location for RSR, the fast passes were gone for the day. Ridemax had us scheduled to get Fastpasses at 9:35 - a good 40 minutes AFTER they were all gone. So that threw the plan off from the get go. Also, Ridemax had us pick up our Fastpasses for ToT at noonish, and scheduled us to return to ToT at 3:45ish. Unfortunately, the Fastpass return time was actually for after 5 pm.
So, all in all, there were a few glitches at DCA. I'm not surprised as Carsland has really created some chaos in the park. I would say use Ridemax in DCA as a rough guide and treat as the law in DL. Ridemax delivered in DL. It felt like we had the park to ourselves because we were practically walking on every ride.
I am sure that as more people use Ridemax in DCA, it will get more accurate. Good luck and have fun!