Yes, I've heard of it. I've been there the last two years.
This year, it's going to be bigger and better than ever (or so they say). It's the only con I've been to, so I can't compare it to others, but they do a nice job of organizing and running it. The dealer's room is pretty well stocked and there's plenty to do.
Check out the website:
http://www.colossalcon.com