I went through this a few months ago at one of our homes. It's just upgraded technology and probably easier for them to manage and troubleshoot remotely. They shipped it to me and I did a self-install but they forget to tell you that you have to first go to comcast.com after connecting and logon to your account so they can activate the new modem with your account. Otherwise it seems to work fine but you can't go anywhere on the Internet. They should have said that in the instructions.
One other thing is these new modems have a second wifi access point on them called Xfinity. It is supposedly for your "guests" to use so you do not have to give them a password to your wifi, but it requires them to have a comcast email and password so that explanation is a bit disingenuous. Whet they are really doing is building out a wide area network using their modems. I experienced this cruising down the Long Island Sound one time where by backup navigation laptop was continually connecting and automatically logging into into Xfinity sites. It is pretty cool as a user, but I turned the feature off in mine. Just doesn't feel right to have strangers stopping outside and using my cable.
Dave
