We were there last week and did EMH at the Magic Kingdom and Hollywood Studios. EMH at MK was great. I waited about 25 minutes for the Minetrain, but everything else that we rode had short lines (about 10 minutes for space mtn, most others were walk-one. The times posts did not necessarily correlate with the wait time. Peter Pan showed 35 minutes, but we only waited a couple of minutes after we got through the que.
HS was another story. We arrived in time for the 6 pm Indiana Jones show. After that, no Fastpasses were available, but Star Tours was only a 10 minute wait, so we did that twice. We had dinner; the lines were crazy long and I didn't think we would find a table, but somehow we did. I felt like we were just waiting for everyone to go to Fantasmic so the lines would get shorter, but they never really did. After dinner, TSMM showed a 15 minute wait, so I guess everyone rushed over; it was actually about 40 minutes. They close the ride at 8:00 for the fireworks, so I guess that is why the line got as short as it did. After that, RNR showed a 25 minute wait, so once again the whole crowd rushed there and by the time my husband and son got in line, it was 40 minutes. My daughters and I watched the fireworks (amazing, btw) and then the app once again showed 15 minutes for TSMM. We headed that way, but cast members were holding up a rope to that section of the park, and a big crowd was forming. We didn't want to deal with the crowd, so we decided on the Great Movie Ride, which was showing a 20 minute wait (I know...but my daughter wanted to ride it). Cast members were also preventing anyone from getting close to that area. It was about 10:25 at that point. So we headed back to Star Tours to ride again because it was the only thing with a short wait. When we finished, the app still showed a long line for TSMM, so we did actually wait 20 minutes for the Great Movie Ride. After that, the app showed 45 minutes (I think?) for TSMM. We were exhausted and decided not to take a chance that the line was actually that long, so we left. Our whole time there was a beating. I will not do EMH at HS again until there are more attractions that draw a crowd.
I almost forgot, we also did EMH at Epcot. That was great; we did have to wait about 30 minutes for Test Track, but everything else was a walk-on.
Good luck with whatever you decide!