I wish I woulda gone to Skywest at my 1 year mark at my current carrier. But I didn't and now I am about 50/50 on if I made the right choice. Giving up seniority is a big deal. I stayed put and hold decent seniority now at a decent carrier. Might not be a bad place to be for the moment.
While I think Skywest is a good employer from everything I have heard, giving up significant seniority is something to be very cautious about. If you are a relative newhire at your current carrier go ahead and apply. The worst that happens is you interview and decline a job offer.