I'm a cable modem user (on Cox Communications) in Fairfax County, Virginia for several years now. Recently, Cox offered a higher speed option (15 mpbs by 2 mbps), so I jumped right on it.

The upgrade went smoothly, but I was only measuring speeds of around 10x2. After a bit of searching, I found out that I ought to upgrade to a DOCSIS 2.0 modem, so I did that. Now, I'm regularly measuring speeds of 16-19mbps down and 2-2.5mbps up. I've tested at various times of the day and those numbers have been quite consistent.

I should add that the modem swap was painless and that Cox support was entirely effective. In one phone call, I gave them my new MAC address and fired up the modem. I did experience a couple of network problems, but it turned out to be a router problem at my end, so I can't fault Cox for that.

I also noticed that the voice quality of my VoIP service (Sunrocket) immediately improved as well.

So, put me in the "highly satisfied customer" group. Kudos to Cox for offering this service!