Mesa's training dept. CRJ is OK, not the best training I've ever received, but OK. Sim was OK again....but I didn't really like the way the CFM was written.....there were a couple of head scratcher things in the checklist that made you think, "who wrote this stupid $hit? have they ever even flown the airplane?" But for the most part, it got the job done, and allowed you to get a good basis for actually flying the line.
The DHC8 dept. is another matter. At least a 50% fail rate in it. And it's all due to a bunch of 'club' instructors. If they like you, you pass, if they don't you fail. I was never a student in that dept. but they shared a building with us, and some VERY GOOD people I know never made it through the ground school. The people on this board are right....most of the time a high failure rate, (especially one that high), is due to poor instruction.
The ERJ ground school is very good also. Had beers one night with one of their instructors, and I swear, if you marooned the guy on a desert island he could build a dam ERJ out of coconuts and sticks to fly home in. He was FANTASTIC. He was an old mechanic on it, and he knew it front and back. But the best thing about him was, he didn't expect you to build the airplane, he just wanted you to know it. But any question you asked him, he knew the answer, without even thinking. The folks teaching the CRJ ground school were all line F/O's. It was a crap shoot whether or not you got a good one, but I got lucky and did.