IowaCowboyWant to go back to IowaPremiumReviews:
Springfield, West Springfield, Westfield (Comcast headend is in Westfield), Agawam, Holyoke, and Longmeadow are served by Comcast. Chicopee, Ludlow, Wilbraham and East Longmeadow are served by Charter. I am glad I have Comcast as I have heard many complaints about Charter both on DSLR and local forums.
As for Enfield, CT they are served by Cox.