Darth Sidious said:
EMH at night are very good. August of 05 we were at EPCOT and it was open until 12. We went on Soarin' twice in a row at 11:55. The lines are usually not that long especailly if the park is open late.
This reply is correct for Epcot, AK, and MGM.
It is NOT ALWAYS correct for MK.
The evening EMH's at MK can be PACKED (or NOT).
It all depends on the time of year (and how LATE MK is open.)
Some WDW guests say there are MORE folks during EMH than during "regular" hours that same day (folks come back from resorts or other parks for MK EMH).
That said, it all DEPENDS on what you want to do and are willing to "chance".
If all in your party are staying at a WDW resort,
bring EVERY ROOM KEY so each person can get a wrist-band.
Hey, its FREE!
So you can TRY it:
If its a low crowd night... COOL!
If you find its "too full"... depart.
Remember, you can come and go at any time BEFORE or DURING EMH hours (and still get your wrist-band).