Not sure what SNS3s experience is with Avantair but as a current pilot there I don't agree with his assessment.
Maintenance is fine, things get fixed. I've been there for four years and his post is the first I've heard of any unionization attempt. Since that point is false it's illogical to think pilots have been fired for trying to start a union. At least in the past four years that I've been here.
As to the OP of that other forum...well, I'm biased but my opinion is he had an axe to grind due to his not upgrading on HIS timeline.
I've flown airline and freight and this is my first gig flying corporate and this is by far the best I've been treated. I'm not management, just a guy flying the line and I don't guzzle the cool-aid either. When I think the company is wrong I call them on it. AB payscale comes to mind. They moved toward starting one and I screamed on the forums about it. Now it's gone.
Anyway, it might not be an ideal fit for everyone, but for me, I like the flying and the company treats us fair at Avantair.
gp