I would look into how much they pay during their "training" periods, since you have a family to support as well. Have you talked to your children about your decision-and of course my next question would be--spouse? is there one? As far as which school, it will honestly depend on who you ask.
Look into their medical coverage,
their "home time", and pay.
These all could greatly effect your decision between the 2 companies. There are also a few other things to look into.
How about dead heading? If you are going for a distance to pick up your load--is there any reimbursement for that?
Next I would want to know about detainment pay. If you have a scheduled appointment, and you are there for long periods of time, do you get paid for that as well?
There are so many things to consider, but these are just a few that have popped into my head.