See Promises, Promises. It's a fantastic, big Broadway musical that never takes itself too seriously. Idiot felt like a very expensive, very pretentious senior performance art thesis project.
The audiences for both show are on polar opposite sides of the musical theatre chart.
I happen to like classic Broadway (though I think Promises often falls into post-Golden Age/Sondheim era territory) and rock musicals. I love RENT and Spring Awakening. I don't think Idiot comes even close to being a milestone (or even small dent) in Rock Opera history.
Sean Hayes is giving the best male performance in a musical on Broadway this season, in my opinion.
If you like rock musicals, see Bloody Bloody Andrew Jackson at the public.
"Broadway...I'll lick you yet!"