Looking at the hourly rate tables, I do not see much difference between Spirit and B6. Sure, pilots at B6 earn about 10% more than pilots at Spirit but not 30%.
The big difference is the steepness of the curve: at B6, entry salaries are higher but level off faster, whereas at Spirit entry salaries are low but climb faster.
Example: 1st year Spirit = $71, 11th year Spirit = $141. 1 st year B6 = $138, 11th year B6 = $157.
These tables also show me that I should never become a pilot
And I feel sorry for the FOs, who seem to be severely underpaid.