As stated, SkyWest is non-binding which is nice. Will get you your bonuses and such earlier. I wish I had done it years ago. It will raise your income a few thousand due to having first year bonuses (my understanding), assuming you start the program at least a year in advance. Also gives you seniority for training sims, and I think for non-rev seniority. Your pilot seniority doesn't start early though.

American programs are binding, but far superior...if you plan on going to them. Especially if you work at an approved school. Every 100 hours you get flight instructing, they pay you (like $500 or $1000, I forget). You also get flight benefits once you start instructing. SkyWest only gives you benefits a month before you start training. Some other things too, I'm not as familiar though.