I don't recommend Netgear, I have seen too many problems with their firmware. I know people with the CM1000 which had trouble getting gigabit speed due to firmware problems with the ISP. Netgear/Comcast downgraded it to only being certified for 800mbps with Comcast, which is really dumb for a Docsis 3.1 modem. My friend that had it couldn't even get over 500mbps with it. He gave up and bought a Motorola like mine. He was mad because it was the same price as the Motorola and we live an hour away from a Microcenter where I bought mine. He chose to save an hour of driving time and bought the Netgear from Best Buy, instead of drive to Microcenter and buy the Motorola. But in the end, wasted a vacation day from work and tons of hours of frustration with his CM1000.
I'd stick with Motorola or Arris. Personally, I use the Motorola MB8600 (predecessor to the MB8611 but I only have a 1gb port) with my Xfinity gigabit and it's been rock solid for several years now. I had 1 outage in the time I've had it, but the whole neighborhood was out and there was construction going on down the street. The problem lasted several hours. I'm getting my full gigabit speed, though technically I have 1200mbps internet plan, but the physical port is only 1gbe. (puchased this modem before the MB8611 with the 2.5gbe port came out)