Skywest. West coast is awesome. East coast is... I like Denver, but also any of the California bases are good places to live. Skywest is much more stable. They are doing lots of flying for two airlines (United and Delta) and they are expanding rapidly, and will continue for the near future. Expressjet only flys for Continental, and come next year their business might go to **** (with this new corporate flying). Don't worry about the first year pay. That is only one year. Look at all the other years. Upgrade will probably be much quicker at Skywest (That is a good thing about a regional that flies turboprops as well).

Skywest is the better choice for you, in my opinion.