If you knew your Jepps, systems of the most complex a/c you're flying, basic IFR regs (91, 135, or 121 whichever you currently operate under) you'll do ok. Paperwork like everyone else said is the biggy. I think they're probably being more selective since it is the end of the year. I was hired in September (start class a week from today) and quite a few people in that day were hired. I would say 75% of the 30 that interviewed.
Nick
Nick