Colossalcon

Artist alley judging seems questionable. Some years it's been very unbalanced in what sort of work gets in, and I've known very talented people who've been rejected when they should have gotten in without much competition. The staff are unreliable with timing and information, directing people to their FB page instead of just updating the site which everyone actually checks.
But if you're lucky enough to get in, the venue is great (even if expensive to stay at and it's hard to drive in every day so you kind of have to stay there). It can be really profitable.
Good luck.