In priority order:
1. The one that will get you based with a drive to work. If you are considering a large CRJ/ERJ operator HQ'd in Utah, all ERJ bases are CRJ bases, so that one is a wash.

2. The most junior of the two aircraft.

Anything else is far, far below these two factors. Avionics, bag storage, seat comfort, lavs, slight differences in pay rate, any of that junk: Is just junk. Seniority is in your seat everything.