It is the worst OS Apple has released since I've been using Macs, back to System 7 on a Centris 610 back in the early 1990s.
I'm neither. ML has been the most problematic OS that I've dealt with since I started using Macs. Even the total lock-ups that sometimes came with System 9 were less common than the persistent issues with ML. In fact, I reinstalled Snow Leopard onto two iMacs and one Mini in my lab. I'd do the same for my Mac Book Pro, but it needs Lion at the least, which isn't much better than ML in my experience. Will Apple sort it out? I sure hope so but, frankly, I think they're more concerned with iOS and OS X is becoming the ugly step sister.