Prepare for a half day of many 30 minute interviews. You meet with leads, other developers, department heads, etc. They ask a lot of questions but don't really provide you with a whole lot of time to ask questions of your own, which I would say is the biggest downfall of their interview process. Overall, though, they are all very friendly. The preliminary phone interviews were great/easy.
The worst part of the interview / application process is those online exams they make you take. Those have got to go!
It seems a really great company to work for.. Under the right circumstances I would have accepted the job.