keep in mind if you go to skw you could commuting to MKE for a month or two. if youre from WI skw is a great choice because your seniority will shoot thru the roof there, people dont like being based there for a number of reasons (theyre not from there, midwest demands too much, you have to wear your hat and blazer, you have to stand at the door and waive goodbye to the passengers, all this and turn an airplane in 27 minutes).
i think this decision is going to come down to where you live and where youre willing to commute. upgrade times at skw could stay low, but think about it, youll be at skywest behind 1000 people that were just hired in the last year and a half so its kind of a crapshoot as to when upgrades will slow down.