Sure thing. Invariably, the ultimate question this thread will probably evolve into is: "Who should I work for?" We argue about that day and night on these boards, but allow me to humbly offer my suggestions. Keep in mind this is as of right now; things could be different in a year.

Mesa - Fast upgrade time, stable, growing, modern fleet.

Compass - Pretty much the same as Mesa.

SkyWest - This is sort of the opposite in that it's not growing and you'll have a very long upgrade (~7 years as of now). However, many of my friends have elected to go here for its well respected treatment of employees.

Horizon - Excellent pay (at least compared to other regionals). Long upgrade, however.

One other deciding factor for you might be the bases these regionals have. I live in Phoenix, so naturally Mesa was an obvious choice for me. Again, this is my humble 2 cents, do your own homework, and best of luck.