I was in your exact spot a few years ago, except I was flying a CJ3. It was an agonizing decision... Do I leave a place I know with high QOL for a freaking regional? At the same time, where was I going to be in five years?

After speaking with pretty much anybody that would listen, I finally came to the conclusion that I absolutely had to move on in order to have a chance at my goals (flying for a Legacy carrier).

That first day in at the regional was a real *** did I just do moment, but here I am more than 2.5 years later. I don't regret it at all, and have applications in with United, Delta, American/US Air, etc. Without leaving my cushy 91 gig, I still wouldn't be even remotely close to competitive.

I also ended up enjoying 121 far more than I thought I would, even at a regional. Good luck with your decision!