We flew Comair last year also. The Cincinatti airport was great on the way there. Nice clean airport. I was less than impressed with Atlanta. Cranky people and not the cleanest. Also the trip from one terminal to the other was pretty far dragging all the kids, bags, etc. Make sure if you use the tram to the ride from terminal to terminal you hang on tight. It goes fast!
Not sure about everyone else but with the two Comair flights, we had to go out to the tarmac to get on the plane. There was no jetway. The kids thought that was kinda cool. It wasn't too bad in Atlanta but it was mighty chilly in NH.

We sat in the front row on the way home and found that very roomy and had a very nice flight attendant. The kids all brought their carry-on bags with their "stuff." For the price I paid for last year's tickets, I was pretty happy. Although other people have said Delta is horrible with losing luggage all of our luggage arrived with no problem and was unloaded quickly. I think you'll be okay! We can't get any direct flights out of Manchester except on SW but we can never get a decent price on SW for Feb vacation so finding new cities to connect through is part of the fun for us. So far, we have been through Detroit, Cincinatti, Baltimore, Charlotte, and Atlanta. Next, we will be trying Washington DC which was definitely not my first choice but we got Charlotte on the way home (one of our favorite airports). Hope you had a great trip!