I think TSA is the better option over XJT or SKYW if you are looking to move on in your career. I worked at one for 5 years, and interviewed at the other last month. The interview left me feeling like they were looking for career guys where as TSA knows they are going to loose you after a few years especially with the short upgrade time. As far as regionals are concerned, I would go with the one that will help you move alone, not tie you down and want you to stay forever. Eventually, folks at the majors will retire and pilots will move in to bigger airplanes/pay/company. Just my .02
Of course, being unemployed now is not really making me to be a great source, I will take what I can get, but I can tell you that the interview I went to resulted in the "thanks, but no thanks" letter. I emailed the recruiter about it, and it was because of my time and experience that would lead me to leave the company before too long, thus leaving the company in the same place they are now, looking for more pilots.