This is my 5th year going to the festival. I've seen some very interesting documentaries. But beyond the films themselves, the administration of the festival has been excellent.
Single tickets can be expensive. But if you're looking to see a few movies with some friends, the 10 ticket pass is extremely flexible. It's basically just a massive discount for a prepaid block of 10 tickets.
($15 per ticket discounted to $11 per ticket)
UPDATE: the amazing Whole Foods discount is dead because of the new location.
After you get your pass, you then use it to purchase individual tickets. Best way to do that is to call and reserve, then pick them up at the box office.
The website is an excellent resource. Unlike TIFF, where you can't rely on the website for ticket information, hot docs seems to update the status of the tickets pretty quickly.
CON: The major con is that the quality of the docs can vary. Some docs are amazing and will blow your mind. (You'll be talking about them for weeks with your friends). But others are short and not quite what you would expect. I think that's just the part of the experience. If you go to 4 docs, expect 1 of them to be a dud and you'll be very pleased.