It's definitely worth going! The stage is an exact replica of the TV show... in fact, episodes have been (and I believe sometimes still are) taped there! It's like you're actually in the audience, it's very accurately portrayed. The only differences here are the slightly modified rules (allows for more audience participation), and the slightly more humorous, Disney-fied tone of the presentation (only slightly, though). And of course, there's no $million- but still cool prizes! The host when I was there was VERY good. It's a must-see for any fans of the show.
Also, it's nice and cool inside, so it's a perfect get-away during hot weather (just like One Man's Dream beside it).
The only problem is that it's on east-MGM, which is significantly more bustling than west-MGM, so everything there tends to be a bit more crowded. It's a Fast Pass attraction, though.
-Aaron