Prospect Heights, IL
I obstained from voting because you know my recommendation already.
You're a more skilled player so if buying just for yourself to enjoy, go GB. It is more difficult, unforgiving, and has hopes for a deeper code. For family, friends and guests - MM all day long. Kids love bashing the castle, theme is approachable to all, and the humor entertains. Plus it's a damn fine looking game - one of the best!
My only other recommendation, wait if you decide on GB. Let Stern get the game to a "MET" level in code before buying one. Unless a screaming deal comes up. They're not done with the quality issues and code is still in maturation phase. Unless you really like code as is, don't gamble with Stern any more. You know me and how well I'm versed on MM rules, code is king. 
Calgary, AB
