My opinion is go to Skywest! Getting experience at Mesa is great but caution... You signed a training contract already and once you complete training (don't recall what is considered completing of training but probably after IOE) you could be required to pay it back. Upgrade training contracts are approx. 12,000 bucks and that translates to 1,000 a month. I don't know how much a SIC contact is worth but who cares. If you want a type rating that bad let Skywest buy you a couple or just pay 12,000 bucks and get a PIC type but don't get a worthless type rating from Mesa. SIC type ratings just mean you sat in the airplane legally for international flying thats it. Mesa legal department is busy, but knowing JO it wouldn't take but two seconds to send you a certified letter asking for the money and or threatening legal action. Mesa contract could be like an apartment lease the landlord wont let you out of unless you pay. Ask around, but I would wait and take the job with the better quality of life. Compare days off and pay to see if it is really worth getting a slightly faster upgrade (maybe) or having a life.