We have never been to early magic hours, but did try evening magic hours on our trip in June. We did Animal Kingdom and Epcot and we were disappointed in Animal Kingdom, but most of our disappointment came from not being able to plan until we got there. When we did Epcot, we knew beter so it went much better. First, if possible get your wrist band early. The lines can get long and in Animal Kingdom they ran out. Even though there are extra hours, things can be limited. I can't remember what may have been limited in Epcot, but at Animal Kingdom the extra hours were 7 to 10 and the last safari was at 7:30, there was only one Lion King show at 7:30 and one Tarzan Rocks show at 8:15. NO big deal, but I wished we had this info before we left the resort, but they said they didn't have it. IF we had this info we could have planned accordingly.
I think the EMH are like most of Disney, planning is the key.
We will also be there 8/20 to 8/27 taking full advantage of our annual passes that expire in May.