I listed advantages in my previous reply but forgot to add one point which would be my deciding factor. If one of the companies has a domicile in a place where I'd love to live, that would be my choice hands down. On average, working for any major airline is going to pay (significantly) more and you'll work less than any full time flying gig you've previously held.

If you're a commuter you are likely giving back anything from 4-8 days/month depending on your commute and tolerance for risk. If you're in base you will have the chance to make the job even more financially lucrative by being available for short notice premium trips or bidding up a category where you wouldn't mind sitting reserve from your couch.

Without a crystal ball, living in a place I like would be my #1 priority if I had calls from multiple legacy airlines.