I hope that they have better luck with the speed upgrade then the Northeast did. Many unhappy customers around here. The old lines around here couldn't handle it and it led to very erratic performance. http://forums.comcast.com/t5/Basic-Internet-Connectivity-And/bd-p/5
I live in NE PA and my blast got upgraded to 50mb (im also a tech and have a new rewired apartment and drop and know the signal bandwith and channel levels and such however) Ive never had any issues, never heard alot of complaints from other customers either.