i think the biggest key to youre quality of life is schedule. When it comes to schedule, i dont really feel like theres much difference between one carrier or another when it comes to regionals. the best advice i can offer is to do your research and get yourself in a position to be marketable at the BEGINNING of the hiring wave. Say you are keeping yourself up to date on regional news and hiring and you find out that Air Airways just got an award for 50 airframes from United and they dont have anyone on furlough...you need to get into the first class you can because that means a couple things:

1) you will end up sitting less reserve
2) there will be more people below you which equals better schedules and job protection

I know that people on these boards dont think much of TSA, but I got in at the beginning of a hiring wave and sat 3 days of reserve. My quality of life has historically been pretty good, but im getting shipped out to IAD now. When i was hired, there was no way to predict that.

ok...so i just rambled for a long time, but the point is: make the best decision you have with the most information you have.