Look at Go-Jet as well. However I do not care to stay an Alpa member myself. I believe you can pay a maintenance fee to remove your self from the cartel.
With that said, I have always found dealing with management directly to always be the best course of action. I've only been with Mesa post bankruptcy, and I have heard all the horror stories of how things used to be. However, I was never exposed to any of that, and the Mesa I know today, is not what people have described to me in the past. As a pilot, everyone that I have direct contact with does not come across as wanting to screw me over, the opposite in fact. Even J.O. has been pleasant to talk to in e-mail. I don't believe any one at Mesa wants to screw pilots over, they just want to run their business the best they can.
As far as OUR Alpa reps helping you, I've heard multiple times from pilots doing carpet dances, it was never the company being the dickheads, but OUR ALPA REPS drilling the pilots, instead of them helping. A close friend of mine experienced that, and Chuck protected him, despite the REP who was supposed to represent him suggesting he be fired as he was a few days short of his one year anniversary.
And to be fair, I have also heard stories of the same reps helping our pilots, but it appears they only want to help the pilots that they personally know. It is not really much of a concern anymore as the resignations come in.
The new F.O. rep for Dallas/Houston seems like a decent guy, he is also the jumpseat chair, and if I needed help with something, I would probably contact him first.