I got asked a couple of questions on the Seminole, but that was it. There may have been about one or two questions on the CRJ on the written exam, but that was it. Mostly it was like was said above. They want to know you're not a tool, you have the capabilities to pass ground school and be a successful pilot and most importantly, know you're not a tool.
The hardest question for me to answer on my interview was "How are you going to handle the jump from a small piston twin to a 53,000 lb jet and what have you been doing to prepare yourself for that jump?"
As for the people in my interview group, it ranged from DCA, ATP, small FBO guys (like myself) and some guys with 135 and 121 experience. They wound up hiring a mix of everyone.