I only have experience with the morning EMH, never really used the night time EMH, other than going into the MK at 2 am while there at Easter. For the mornings, and this was at Easter, the MK and Epcot were great. Get there a bit before opening and you will be able to get a lot done before the parks get crowded. At AK it was a complete mess. No control of who got in, no checking of resort ids, only a few turnstyles open, took close to an hour just to get in. Did not do MGM. But the MK especially was magical. We have pictures where we are the only ones around. Got to ride everything we wanted by 11 with no waiting. At Epcot it was also great, no lines for Soarin and test track, got to do each of them twice.
The thing at fantasy land is for families with young children.