What do folks out there use for event management?

We've been using and talking to Cvent locally, and they don't seem to understand even such basics as iframe integration or WordPress integration. Their system may be built with a different intent in mind, but in the meantime I wouldn't mind some brief comments from those kind enough who've actually developed event booking systems.

The specific need is to be able to register and pay for courses online, and to provide a list of those attending, and to enable creation of course sessions and dates into the future.

So, has anyone used Cvent?

Can anyone comment on using other systems and the success (or struggle) they've had?

The site is WordPress, so anything integrating with WordPress is great, though not essential of course (as many of these sites provide iframes etc).