We flew United out to Boston over the end of December. Was not fantastic, but not any worse than Northwest - decent customer service, etc. (We were doing carry on baggage, though...)

Our only gripe was having to trudge through long hallways in O'Hare while going from one plane to another (down, through the tunnel with the spiffy lights, then back up again). But if you are avoiding O'Hare, that wouldn't be a problem.