I've been conning for years and help run a convention (shameless plug - www.animepunch.org). I've been to large cons (ACen, Ohayocon) and many smaller ones time and again. So I have a sense of what to expect and what constitutes a convention putting on a good show. That being said, Otakon is different. It's bigger for one thing - 40,000 attendees. The only US anime convention that trumps it is Anime Expo (and as I understand it, that has fewer trappings of a traditional con and is more designed to show off the latest and greatest releases and what not).

Lots More After The Jump