Colgan is a great operation with a fast upgrade time. I don't know much about Beech upgrade time, but the upgrade in the SAAB is really fast. (typically a year, or as they need you, provided you have or are close to having the minimum time requirements) The generic requirements are 2200TT, 800-1000 in type, and the ever-so-obvious ATP minimum requirements - which you most likely have with these TT requirements. Oh yeah...and the ATP written would help too!
AE is a good company, but the upgrade time is horrible. Granted, you would most likely be put in the ERJ right away, but you would have about 5 + years until you upgrade. If that floats your boat (sitting 'shotgun' for 5 + years), more power to ya bud. You would be flying new(er) equipment, get glass experience, all that jazz. I actually know someone who flys for them, based in LGA, who loves his job. He wants to walk my resume in for me when I meat the mins. but I am a little hesitent, just due to the upgrade time.
PSA, I don't have much to say on. They have an average payscale and they fly awesome equipment (CRJ-200/700's). Their crews are very nice/very professional. That's all I've got on them...
GOOD LUCK!