It's been a couple years since i've seen either of these shows but with that in mind......
Vegas! The Show was damned good. Better than I expected. I'm not old enough to remember Elvis and The Rat Pack in their primes but this gave a good feel for what that must have been like. Good scenery and performances all around.
Is Beatleshow the same actors/performers who were the Fab Four? Thought they were very good as well. Of the two shows, if I could only see one again, would choose Vegas! The Show