I've worked many AM extra magic hours, and always tell guests to take advantage of them. Many people do sleep in (even at WDW

!). It will look crowded when you first get there because of the limited area where guests wait for the gates to open.
The the crowds for the evening EMH depend on what time the park is scheduled to close. The crowds are going to be larger when EMH is from 8-11 than 12am-3am. Everyone is already awake and at the parks.
Get up early and take advantage of EMH.
Some people will complain about the limited number of attractions open for AM, but you only have an hour--not 3
These are the attractions currently opening for AM EMH
MK
Astro Orbiter
Buzz Lightyear's Space Ranger Spin
Cinderella's Golden Carrousel
Dumbo the Flying Elephant
Mad Tea Party
The Many Adventures of Winnie the Pooh
Peter Pan's Flight
Snow White's Scary Adventures
Space Mountain®
Stitch's Great Escape!
Tomorrowland® Indy Speedway
EPCOT
Mission: SPACE®
Spaceship Earth
Test Track
Universe of Energy
MGM
Muppet*Vision 3-D
Rock 'n' Roller Coaster®Starring Aerosmith
Star Tours
The Twilight Zone Tower of TerrorTM
AK
Discovery Island®Trails
It's Tough to be a Bug!®
Kilimanjaro Safaris®
Pangani Forest Exploration Trail®