Crowded... There was a larger women who was sort of falling out of her tiny costume right in front of me in the line up to get in, you'll find alot of them... There's some cool stuff to buy... Everything is expensive as hell... No shortage of fedoras
I've been to two cons, planning on going to another one in September. If you can afford it, get a VIP package. That will get you onto the con floor earlier and give you priority seating in panels. You'll also have priority for photo ops and autographs.
They are crowded, but everybody is generally fairly pleasant. Most cosplayers love having their picture taken if you ask them nicely. Make sure to wear comfortable shoes and bring a water bottle and some snacks. Con food is quite expensive.
Be prepared to stand in line a lot, but don't be afraid to strike up a conversation with the people around you. They're cool, too, because they're at a con.