We've had Comcast cable-tv and broadband internet since Jan. '03.
Billing was a nightmare for about 8 out of the ensuing months. It was a f*ckup from the beginning, and believe-it-or not took 8 months to finally become glitch-free. It was seriously like a comedy of errors, where each month's attempted billing fixes were f*cked up again and again.
On the bright side, have had little or no down time whatsoever, and regularly average 2.7-3.0 Mbps download. Blows away any DSL I've used.