Both rides are awesome, and I make it a point to ride both as much as possible when I'm at either park.
I can't directly say which one I like better because I like them both. The only thing that would influence my opinion would be the park (ie "I like Everest better because it's in AK" or "I like ROTM better because I can go on MiB after it").
Everest has the thrills, but the ride's theming could use some work (in some areas), and the ride could be a little longer.
ROTM has awesome theming and everything up to and including the launch is outstanding, but the coaster portion is kinda boring and the ending is god awful.
Ultimately, both rides offer a complete experience, including a great setup, incredible theming, and thrilling moments.
