Based on experience alone, your more likely to be offered an interview at Commutair.

Upgrade time at Commutair will probably come quicker, especially considering that they will be bringing Dash 8-Q200's on line early next year.

Turbine time is turbine time (for the most part). So, as far as moving on to other companies, Commutair might mean a quicker career progression.

Smaller pilot group at Commutair. This might be good or bad, depending on how well the group works together. Also Commutair has more of a "family" atmosphere from what I hear.

Smaller pilot group most likely means fewer labor issues, however it might also mean fewer work protections should you ever need them.

Odds are also that your flying skills will be sharper after a year at commutair flying the 1900 when compared to the same year flying an ERJ.

Equipment at XJ will be more "comfortable" (IE APU/autopilot/flight attendant/faster/higher/jet/etc)

One thing to consider too is that nothing is for certain. Commutair is a small company today. It might not be tomorrow. XJ is considered to be one of the better companies to fly for now... it might not be tommorow.

Like I've said before- the only certainty with the airlines is that nothing is for certain.

~Josh
(Furloughed from one of the best (now-defunct) regional airlines in the nation, May 2005)