I hear you.
Our bandwidth is dual-homed, part Cavalier, part Cogent. Problem is one leg of our leased fiber belongs to Cocmast. It has gone down four times in the past six months and every time it is the Comcast segment of the link.
luckily my Comcast cable modem has yet to show any signs of instability. the EoC connection from Megapath is provided by XO. i've had stability and packet loss for years and XO doesn't care one bit. if it's not showing any signs of failure for the 5 minutes they run their test then there's nothing wrong. even when Megapath provides logs to XO showing they had packet loss, along with my packet loss and alarms, they just brush it off. apparently i have to figure out some sort of schedule for the unscheduled downtime for them to test and see a problem.
once our fiber goes online i can be rid of Megapath completely. earthlink is going to be providing it with AT&T and Verizon providing the links.