Hi zahi,
Thanks very much for reading the Unofficial Guide!
YMMV = "Your Mileage May Vary." That is, your specific situation might be such that EMH doesn't help. Suppose you're visiting Epcot with your soon-to-be-ex-boyfriend and his mom. If mom won't go on Test Track or Mission:Space because it'll mess up her new beehive hairdo, there's little point in going to Epcot for EMH. This is because the other attractions open for EMH (Universe of Energy and Spaceship Earth) can be experienced with little wait during non-EMH days. So the "YMMV" is there as a caveat.
That being said, many folks, especially first-time vistors, tend to do fairly comprehensive tours of the parks, often with mid-day breaks. For them, my original advice is generally valid.
If you'd like to post more details about your plans (e.g., this is your first trip, you're staying for seven days, everyone in your family is up before the sun rises, etc.), we can make more specific recommendations, I'm sure.
Feel free to drop me an e-mail (testa@ncat.edu), too, if there's anything else I can help with for your trip.
Sincerely,
Len