I worked at Air Wisconsin about a decade ago, so its likely what I'll say could be very wrong or maybe its still relevant. The training department, led by PP, was NOT a cooperate graduate program. It was difficult, but not so much that it was impossible. Back in 2005 when I was hired 25% failed out... that said those that did were for the most either a bit weak or unprepared. There were one or 2 that you scratched your head because they must have just had a bad day.
Compare that to my current airline, which spoon feeds it to you and you have to be a relative dumba$$ to fail, and even if you do they will still allocate just about as much time to you as you need. With all that said, as far as I know out of the ~100+ pilots to come to my airline from AWAC, I don't think anyone has ever failed initial. As such AWAC has a good reputation for producing good pilots.