Many question marks with envoy, how long to sit reserve? Upgrade? Changing fleet etc. those are all questions the envoy people can answer.
As for Skywest, ORD is a junior base for CRJ and ERJ. There's something going on here, we have 100+- lines and 200+ FOs on the 175 so more flying seems all but certain. If you want the CRJ you'd probably hold a line out of training in ORD, 175 is a question mark just because we seem to be overstaffed, no airline just runs 100% reserve tho so if your heart is on the 175 then you may be reserve. Personally I'm on reserve in base and it's great, if you can make the finances work. We have so much reserve I d get called too often, I've yet to be sent to another base for reserve too (touch wood), you can always put call first as your preference and fly more often on reserve if you like.
I only know what I see on here about envoy and there are people jumping ship constantly. The flow is really nice tho, I have 2 friends at envoy that are counting on it after a bust check at envoy, that being said the training is really good there on all accounts I've heard. (People fail at Skywest too so I'm not saying don't go there because people fail).
Skywest upgrade is 4 years, I believe it'll drop to 3 in the next two years, just depends on how many 200s we lose, Skywest management does have a knack for finding them new homes (they are motivated to do so because we own a lot of them a a pose to mainline)