Do you want to buy tickets in advance or can you wait until you're here? Because it's hard for anyone to tell you anything about M. Butterfly until it starts previews.
I seem to recall some saying ADH2 (which seems to have been pretty polarizing if you read the thread devoted to it) wasn't as good after the original cast left. It's also struggling at the box office. Not sure if it'll still be playing in October.
As far as M. Butterfly goes, it was on my list of possible shows to see, but 6 other shows (all musicals) won out over it. As the previous poster VintageSnarker stated, it's hard to know if this will be great or awful.
As I see it, you have these potential pros and cons with M. Butterfly:
Pros: Strong Source material, I believe the playwright was involved in the revival, the director is known for stunning visuals, Clive Owen is a dynamic movie/tv actor
Cons: The director's visual flourishes could overwhelm/undermine the source material, I believe Clive Owen's previous production and performance was not well received.
Given all the above, considering I haven't seen ADH2 or MB (obviously), I'd say go with MB. It'll feature the original cast including a movie star (if that matters to you), is guaranteed to still be playing in October. And given the strong source material, at worst it'll be a beautiful misfire of a classic.
If we're not having fun, then why are we doing it?
These are DISCUSSION boards, not mutual admiration boards. Discussion only occurs when we are willing to hear what others are thinking, regardless of whether it is alignment to our own thoughts.