NETGEAR Nighthawk Cable Modem CM1200 (Open Box)

Was delighted to find renewed unit sold at less than half the retail price (which is high because the CM1150 is the only Xfinity approved "customer owned" modem offering phone VOIP as well. Using Xfinity phone app, I was able to set up and activate this modem quite easily. My phone service worked and I measure internet service at 800mb/s... per my Xfinity plan. I streamed a movie that night.. No sweat. I was about to take my original Xfinity Gateway back to the store when suddenly I noticed internet was struggling. eg. my wife was on zoom chat that was halting. I was using google translate and it was taking a minute to do simple translations. Within 2 hours, all internet was dead. Phone stopped working too. I unplugged the CM1150. Put outside to quickly cool. All to no avail. Re-starting failed to get any functionality back. I then re-activated my Xfinity gateway box. (BTW: That cannot be fully completed using Xfinity App. Phone worked, but internet data was inoperable. That's because special "codes" at their office must be reset before Xfinity will deliver broadband data to that original Gateway modem. Only a live chat session or getting an agent on the phone can get this done). Once up and running, the Xfinity gateway was working normally and reliably. I'm going to hazard a guess. This COULD be an issue of marginal signal strength over the Comcast cable. I am skeptical anything actually broke in the Netgear CM1150. I've had the Xfinity gateway for 2 years and internet loss was only very occasional. My hunch is that the Xfinity equipment may work better as depleted signal levels. I'll probably hold onto the Netgear modem and re-try it in a month- would prefer not to pay the $15/mo rent. UPDATE (2.21.2024) I've been monitoring signal levels in the Xfinity connection status. The signal strength in my family room location is lousy... varying between -15 dBmV and -10 dBmV depending on day, time of day.,etc. I built up a location to place the cable modem very close to my home's Xfinity cable ingress & powered distribution box in my basement, running CAT5 + Phone wire to first floor wall jacks for router & phone base. The Xfinity Gateway experienced 3 - 4X higher downstream signals at the basement location compare to distant family room. Then reinstalled & activated the Netgear CM1150 . Everything came up working within minutes. With just 3 feet 75 ohm coax to the CM1150 from Comcast powered splitter, signal levels between -3 and +1 dBmV are reported by the CM. That's plenty of margin to deal with daily variations that will be in 5 dBmV range. Feeling confident I can dispense with the Xfinity equipment and rely on the Netgear CM. Revising my rating to 5*. Very pleased!