It varies from person to person. They like to bring in several people and kind of "cross examine" you. Very casual. Wear jeans with a shirt tucked in. You can dress nicer if you want, but I really don't recommend a suit. Just know about the company, know what you're aiming for, and then let them decide if you're the best fit.

The interview process is pretty quick and everyone is incredibly nice while interviewing, however, apparently if you don't hear back within a few days don't expect to hear back, ever. I personally do not mind if they decided to go with another candidate, but it really says a lot about their recruiters and HR when you don't hear back. It's unfortunate not ever employer treats job candidates with respect. I rather hear disappointing news than no news.