My Linksys CM100 was still being shipped when the Comcast guy showed up the other day. He insisted we set up the internet with his modem and that I later swap it out and return it. The model he brought was a Scientific Atlanta 2100. I ran a few speed tests at various times of the day and noted download speeds ranging from 13,450-13,904 kbps. The upload speeds ranged from 1,774-1,846 kbps.
I installed the CM100 and ran some more tests. The Newegg reviews reported some users seeing better transfer rates on the CM100 versus their default Comcast equipment.
The CM100 ranged from 13,647-13,810 kbps down and 1,798-1,843 kbps up.
Both Linksys and Scientific Atlanta are owned by Cisco.
No real difference to me, other than not paying the $3/mo lease.