Motorola sb4100 cable modem vs newer?

[scott-DPNOqEs/LNQ at public.gmane.org (Scott R. Ehrlich)]

In a recent conversation with Comcast customer service, they reviewed my 
account and reminded me I still had an old, leased, SB4100 cable modem, 
and encouraged me to upgrade to a newer one.

I am wondering if there is any difference between the SB4100 and a newer 
device?  Would I gain anything from an upgrade, or would only Comcast?

I currently have their economy Internet service and don't need anything 
faster.

Thanks.

Scott