CAUTION: The pay tables (showing hourly rates) can be VERY misleading. The hourly rate is meaningless unless you know WHEN it applies:
Workrules
Daily Rig
Duty Rig
Trip Rig
Guarantee (MONTHLY, make sure you compare monthly rates)
Block or Better
Cancellation Pay
Equipment Differentials
Vacation
Bonuses
For example, mesa has almost none of these things, so their payscale is not really applicable since they rarely GET paid.
The best way to compare is talk to an employee of the carrier in question and find out how all of their workrules apply. Also note that first year pay sucks, but I would not use that as a major decision factor when comparing regionals. Second year (and beyond) is what you want to look hard at.