I think you would do better to stay where you are and wait for one of the big ones to call, honestly. But that's just my opinion and take it for what it's worth. You really have to decide for yourself.
I came here cause they were the first ones to call and I was in between jobs, just contracting myself out. Now that I'm here I see the potential for it to either become something great or stay status quo. It's a crap shoot.
I really like it here but if a major called, I'd bolt in a heart beat. Problem for me is that a major isn't banging down my door. No degree, lots of time (read to much experience apparently now a days) and a lot of back and for over the years between airline and corporate, make for a not so desirable resume. I've had a great 20 plus years so far but my résumé is a bit scattered.
After a year here, I'll make good money again and becasue of the older pilot group here, upgrade shouldn't be more than 5 years away if not less. If I were to go to a major now at 45, I think I'd be lucky enough to see the left seat for the last few years of my career.
You sound like you have a much more solid resume and should be a shoe in for the top choice players. Good luck in which ever direction you choose.