From my experience with Mesa way back in 2003-2005 and from what I have read on this forum over the past year or two the main thing to be concerned about is contract abuse, and being pushed to fly illegally.

Scheduling had, and I think still has the attitude that if it's "operational necessity" then the contract gets thrown out the window. They play dumb. Saw it a number of times when I was there. A good friend of mine was taking a CRJ200 from CLT-MKE. MKE wx was 300 overcast and forecast to stay that way. His release didn't have an alternate. So he calls dispatch and they frantically tell him they'll have to bump pax to take on alternate fuel. He's like "So"? Had to put his foot down and insist on the alternate. We were all ex-mainline USAirways that did a flow down to Mesa after furlough. The system Chief Pilot in PHX hated us because he couldn't intimate us like he could the younger pilots. Our local PHL CP was actually a pretty good guy thou.

Other regionals could be the same or worse, I don't know. Best to ask around.