Great Adv. is terrible, absolutely horrible--and yet I buy a season pass. Well, it is something to do with friends during Fright Fest when the parks are empty and you have free will of most rides.
Busch Gardens Williamsburg, however, is a very excellent park. It's beautifully landscaped and well put together--they usually win awards for being "America's Most Beautiful Theme Park" at least 8 years in a row recently I'm thinking, not sure. True, they do have more carnival style rides, but Disney has been investing in a lot of Dumbo clones recently AND dino-rama. The rollercoasters are top notch and also themed nicely, consistently ranked in the top 15 coasters each year. They have motion simulators, 4D shows, themed coasters, kiddie rides, and carnival style rides as mentioned, but no dark rides.
It's a really swell park evoking the same feelings as World Showcase. However, the downfall is that tho everything in each country is authentic, they lack an abundance of authentic cuisine to each country, and the workers are not from the country they work in.
I enjoy BG VA. and think others should go too. It's a nice mini vacation, usually 2 or 3 nights for us, with Colonial Williamsburg, Jamestown, Yorktown, a water park, William and Mary, and other historical and very unique things.