Union vs. Non-Union. Huge cultural difference. "Merit" based upgrades vs. seniority based upgrades. If you're not an "A-Teamer" you'll also be a 12 year F/O at Flex. No recourse if fired vs. having an arbitration procedure. Having a Union Rep with you if called on the carpet for some reason. And as of now we have pretty good relations between the Union and Company.
Also NJA has great medical insurance for which we pay nothing and have no annual deductible to meet (in network). Office visits are $20 period. ER and/or Hospital admission is a flat $150. And this is for you and your family. And we have a nice Medical Leave program, 6 months at 60% pay then 30 months at 60% capped at $5K/month. And the Union has an optional Loss of Medical plan that kicks in after the 36 months and pays until normal SS retirement age. I think you can get up to around $8000/month coverage that's tax free.
And keep in mind Flex has resorted to cold calling and sending out postcards to pilots in an FAA database trying to get enough warm bodies. NetJets can still be a little bit picky and hasn't had to do that. Our minimums to get hired are also substantially higher than Flex's.