Bests & Worsts Reviews from Amazon

I bought this modem after researching product recommendations. Like many of the other 1-star reviews, I had spotty, very slow downstream performance (<5 MBPS on a 50 MBPS connection) which could not be resolved. After having a Comcast technician come out and check virtually every wire junction in my apartment building and briefly swapping in one of his modems, we found that the SurfBoard was the problem. As the instructions for the modem requested, I called Arris tech support. After an incredibly irritating time on hold, where the music was interrupted every 30 seconds or so with a recording reminding me I was on hold and that click was not, in fact, an operator taking my call, I got through to tech support. After explaining the situation, the support person kindly explained that what was happening was not possible, and there was no physical way the modem could be causing slow performance. It would either work totally, or fail totally, so what I was seeing must be Comcast's problem. Giving him the benefit of the doubt, I called Comcast twice more and had them double-check the MAC address and serial number on the modem and had them reprovision it with no effect. I finally came back to Amazon, and given the amount of 5-star reviews, decided to try exchanging it for another Surfboard, rather than just taking my money back and buying a totally different model. The replacement arrived promptly, and once I connected it, it automatically registered and activated itself with Comcast (the first one I tried errored out at that point, and I had to activate it over the phone). The new one has been perfectly reliable, and has delivered exactly the speed I signed up for. I'm very happy with it. However, I'm still leaving this review as one-star, not because of the first, defective modem, but because of Arris tech support's response that their modem could not malfunction this way. There are dozens of reviews right here reporting the exactly the same problem, so it's hardly an unknown or freak issue. Whether the cause being the modem itself or some chronic misconfiguration on the part of the various service providers, Arris should at the very least know about it, and not act as though this is some never-before-scene problem and deny that it could be happening. Ideally, they should diagnose it and find out if it's some manufacturing flaw and issue a recall or replacement program, or, if it is a problem with the service providers, have explicit instructions ready so I can call Comcast or whomever and tell them what to reset on their end to get the modem working.