Comair was a good place to work. I spent about two years there before moving on -- frankly I would've stayed a lot longer had I seen the potential to make it a career.
There were a few things that I saw which I thought would make a long-term career there challenging at best.
1. There were quite a few of the, "can't believe we get paid to do this!" types there. Usually (but not always) Comair Academy graduates. This was their first job in aviation (outside of flight instructing) and they didn't have the experience in the industry to see things for what they were.
2. The portfolio concept was expanding. Chautauqua/Republic and now Mesa were added to the Delta "portfolio" of Connection carriers. Management was asking for bids for additional flying. I felt that the contract would ultimately come under attack and, if the pilot group had the courage to say "no", they would likely be punished by fleet reductions, furloughs, etc. I didn't see a good outcome either way.
3. Due in-part to the portfolio and in-part to the size of the airline it looked like career progression was going to take a very long time. There was no way to project upgrade time because attrition was almost zero and new aircraft deliveries had ceased (this was prior to the concessionary agreement they recently signed). The problem with this for guys like me and Chprpilot and Whitestone climb was -- we needed to see the potential for upgrade, or why stay? Comair has hired some very well qualified pilots (usually refugees from other airlines) and if they don't have some kind of career path for first-officers they will continue to lose people from the bottom.
On a positive side the airline was run very professionally. Despite what you might hear I never had any difficulties with scheduling or the chief pilots. They were very accomodating and the contract simple to work under. 90% of the Captains were easy to get along with and appreciated a little experience in the right seat -- treated you like part of the team rather than a subordinate. The other 10%

... well, usually they were easy to pick out. They were the ones who weren't F/Os long enough to learn.
I think Comair is an excellent company to work for -- I just hope that the portfolio concept is not the catalyst for their extinction.
Good luck!