Ah yes - indeed I have! I've been meaning to update but never found the time, so thank you for reminding me! First off, the show itself was utterly brilliant. His timing, his jokes, his stories, his music - just everything! A total genius, in every sense of the word. Also, a truly lovely man to meet at the Stage Door as well.
As for the seats, well I must say, my sister and myself sat down and the first things we said was, "Wow, What an absolutely amazing view!" and it really, really was. I don't know whether it was just because it was a one-man show and that the theatre is relatively small, but I seriously still felt part of the "action" as it were. The stage was filled with instruments, lighting and a screen at the back for his little short films and animations to go with his songs. I imagined seeing Avenue Q and the set and people and everything and what it would've been like from up there, and I say it would've still be perfect! There was not a single thing obstructing my view at all, and I was in Row B. Row C or D may have a little obstruction due to the ceiling being at a jaunty angle, but Row A and B will be completely fine, and Much Ado About Nothing should be excellent!
To sum it up, I actually felt paying £30 for the view we got was a bargain! I dare say that I even felt sorry for the people who had paid £50/£60 to sit in the stalls/dress circle when I paid half for a view that was no less than what I would've got from sitting in the stalls. We were just higher up! But I will say, it is a looooong walk up to the Balcony and is quite high. After all the stairs had finished and we entered I thought we'd walked half way across London and into another theatre! (A slight exaggeration....maybe...

) But, as I quote from theatremonkey, it definitely is nowhere near a case where you feel you'll need an oxygen mask!
So yes, those are my thoughts! Maybe I'm easy pleased or haven't experienced enough Balconies, but not a single thing faulted my night out!