I recently returned from attending my second Great British Beer Festival (GBBF). I also attended in 1998. I had an excellent time again. I wish I could say the same about the Great American Beer Festival (GABF). I attended that one in 1999 and would never waste my time attending it again, however I would visit Denver again as I had a much better time at the local brew pubs and beer bars than I did at the festival.
My biggest gripe about the GABF is the shot of beer ration while the GBBF gives you the choice of a half (imperial 10 oz) pint or a full (imperial 20 oz) pint. I prefer having a decent quantity of beer to sit and relax with vs constantly standing on a line to refill my shot glass.
I find this shot of beer situation to be the case at all American beer festivals I've attended with the exception of the NERAX festival held near Boston every spring. That is why it is the only American beer festival I go out of my way to attend each year.
I also found the venue for the GBBF much more spacious than the one I attended the GABF at. Also the GBBF had better food options and also had pub games available to play (which I don't recall at the GABF).
I'll be back in London in August 2007 but I'll probably never be in Denver in October ever again.
Cheers, Bruce