I know of only one person that has failed out of training, but I've been told that there were some other issues going on. There might have been a couple more people that I'm not aware of.

For what it's worth, everyone in my class passed their orals (the last 4 of us did ours today). We are still in the middle of sim, but training is very good and fair as long as you're willing to put the effort in. If you take the job, just work hard and you'll be fine. They aren't going to offer the job to people who are incapable of meeting their standards.