Alright, this may be a common question when wanting to visit Disney World.
Now keep in mind, Disney is not a vomit-rollor-coaster park. If you want insane roller coasters, you need to visit Busch Gardens, or Universal Studios. Busch Gardens has some INSANE roller coasters. Montu, Kumba, Cheetah Hunt, these coasters have been on numerous travel channel shows and are truly bad ass. Super fast, insane amounts of positive and negative g-forces, twists, turns, that's where you go for roller coasters.
Disney is different, Epcot is different. It's more elegant, it's more relaxed, it's very beautiful and it's just a different vibe than the insane rollar coasters in some of the other parks.
If you are an easily board teenage boy looking for speed, save your money and just go to Universal Studios or Busch Gardens. Space Mountain is fun, but it doesn't compare to Montu, or Hulk, or Kumba. Fun, but not in the same ballpark.
Alright, to sum up the MAIN difference between Disney World and Epcot -
Disney World is a little bit more geared towards girls, epcot is more geared towards boys...
Epcot has alcohol, Disney World does not (well the new Be Our Guest has wine, but that's a 3+ month in advance reservation)
Both parks are shaped a bit like a lollipop, you have the stick, and the lollipop on top. The "stick" at Disney is Main Street USA, which is basically just a neat street with lots of shopping, treats and souvenirs. The "stick" at Epcot has the big globe (which is an awesome, yet slow futuristic ride), Test Track USA, Space Experience, Character Spot, and Club Cool (free soda thanks to Coca Cola!)
At Epcot, most of the rides are at the stick of the lollipop, with the World Showcase being the lollipop. At Disney, all the rides are past Main Street USA and up into the park.
My favorite rides at Disney World are Peter Pan, Pirates of the Caribbean, Haunted House, Splash Mountain, Space Mountain, and Buzz Lightyear.
At Epcot, my ALL TIME favorite Disney ride is Spaceship Earth (the big globe when you walk in), Test Track, Ellen's Energy Adventure, Sourin', Mexico, and Norway.
Epcot you can enjoy a drink, alcohol, wine or beer. Mexico makes an incredible jalepeno margarita, and at Rose and Crown Pub, you can get an awesome Black & Tan, or "Bumblebee", which is Boddingtons and Guinness. Tastes amazing.
If you have any questions, post them below!