Expensive Modem, Not Worth It
924620
Price is too high for what it offers.
There's nothing extraordinary about this modem. Hardware is the same found and much more inexpensive ones.
I'd say, save your money!
1037982
I was using a modem provided to me by Comcast and my internet didn't work for a year. Comcast episodically came to my apartment to investigate, the internet would improve slightly for a couple days, and then it wouldn't work again. Comcast charged me $10 a month to use their modem. Then I bought the Arris Surfboard and my problems went away. I returned my modem and now I no longer get charged $10/month to lease Comcast's useless modem.

Don't be like me. Buy the Arris Surfboard and don't let Comcast scam you into using their crappy modem.
4656012
Was not compatible with my cable service, so I had to return this and purchase modem from Cable company. UGH
589052
according to technical help at Millenium, this modem does not work with their cablespeed service.  do not buy it if Millenium is your cable ISP.
2673469
This product just isn't very good and netgear's support is useless. Don't be allured by the price, go for something more expensive and more capable. I have 75mbps download rate at home and this thing maxes out at 10-15 even though it is less than 15 feet from the router, if that.
1741924
This is for the DPC3008 modem.

Replaced the default 802.11ac modem/router combo Comcast gives you, which regularly pulled about 175mb down on the 5ghz band and 70/80bon the 2.4ghz. Switched over to this because I found it stashed somewhere, and figured I'd get to skip out on the modem rental charge. Unfortunately, my download speeds were cut in more thsn half from 180 to 70 tops on 5ghz, and from 75 to 20.

Theres no way this is a docsis 3.0 modem, or if it is, it's a really bad one. I noticed this is an 8x4 downstream/upstream modem, and the Comcast one is a 24x4. That could play into it, but I'm willing to bet this little bastard is the problem. Now I get to buy a brand new modem and spend 30 minutes on hold with Comcast to swap another modem.

There's absolutely no reason to buy this, or use this, at all. Buy a new modem.
4131503
Old modem was constantly losing the signal, and slow as could be.  The Motorola SB5120 maintains the signal and is a bit faster, though I haven't taken comparative measurements to document it precisely.
2323070
The modem began to malfunction right after the one year warranty had expired. It stops working several times per day. Net Gear's support only offered 90 days of support and when trying to contact, simply said out of warranty. We tried speaking with our ISP (no issues found), factory reset, changed power supply, changed cords, tried online advice, etc.

If these modems only last a year, I would have never bought it.
1990795
Bought it from Verizon for $150.  It's even worse than my old modem.  Constantly drops signal, does not increase speed and I get less bars.
1613937
This works good if you want to use it just as a modem !!! My Internet provider provided me 100Mbps but I am getting only 25 Mbps in wifi. This router can't deliver signal more than 25 Mbps irrespective of the signal it is getting. When I called Netgear, they are saying that I am out of 90 Day Technical support window and they want me to pay at least $50 to fix the issue ( If they can fix it). Stayaway from Netgear !!
421380
I'm giving this modem 3 stars because I don't know what's going on with it.

Long, sad tale:

Modem arrived; I hooked it up (properly)and called Comcast on my pay-as-you-go cellphone, since I have VOIP.

It would not activate. I asked them to try the SB 6141 or SBG 6580 config file. No luck.

After a few hours and several calls, the tech told me to bring the modem to the Comcast office, and maybe they could set something up. So I did. The woman there ASSURED me that many local customers were SUCCESSFULLY using the SB 6180. But, she said, the only way I myself could use it would be to pay them $50 to have a tech come to my home in person.

I asked her what a tech could do in person that he could not do over the phone, since I already know exactly how to set it up. She did not know. So I went home and called Comcast tech help on my VOIP phone, and asked him the same question. He didn't know, either.

I wonder if the modem could be defective? How would I ever know? It seems that everyone you talk to gives you a different answer.

Meanwhile, I'm getting a perfect 25 Mbps down with the old Surfboard modem, (More than I'm paying for). And I live in the sticks with very little competition. Why do I need a new modem?
543800
This modem is complete garbage. The chipset in the modem has a known issue that causes latency issues. I replaced an old 6121 modem with this one thinking I'd be getting an upgrade, but that was not the case. I've spent the last 3 weeks trying to track down weird DNS latency issues on my home network, and finally found that it's a known issue with the modem. There is no firmware fix for this problem yet.

Do not buy this modem.
700995
Best part: I'm not renting Xfinity's crappy router/modem anymore.
Worst part: This is not measurably better than Xfinity's crappy router/modem.

It drops off frequently - like we lose our internet connection at least once on most days. I check Xfinity's network status and all is clear. Turning it off and on usually works, but that's already an unacceptable inconvenience for an expensive product when there's no reason for it to lose connection. And it doesn't always work. Sometimes, it drops only our phones, and other times, it drops everything. Then we can't get in via the admin tool to reset it and have to get up and do it manually. This is not ideal when we are upstairs, holding a sleeping baby, or wiped out after a long day. This has also cost me a lot of work time.
I spent 15 minutes on hold with customer service before giving up and going to chat, which their hold message said would be fast. Then I spent 15 minutes waiting for a chat response - and you guessed it: I did not get one. So I emailed tech support.
Also, they have not burned money on an editor and their writing skills are below my son's, so the tech support materials are unprofessional and sometimes difficult to parse. They also need an editor to review their procedures. They suggest emailing them some screen shots when you have trouble - but they don't tell you where to find the information they need you to screen shot. I dug around the admin panel for a while and found one set of tables to capture but not the other (in any of the tabs, and I checked all of them).
2252360
After a year since my online purchase this modem needs to be replaced.

There are too many technical issues to mention, some include, having to continuously reset the modem, super slow internet speeds (similar to dial up), and more.

I suspect my modem/router was sold to me with defects.
3335153
It lasted about a year or so.  We started having trouble getting webpages to load, slow, etc., then no internet at all.  Called Comcast/Xfinity and they had to "reset" the ARRIS SB6141 modem for us as I could find no way to do it at home.  While on the phone with support the tech. was good enough to recommend Netgear which is what I bought today when this one finally quit for the second time.  I don't know whether a year is good enough for a modem but I wouldn't think so.  I mean all it does is sit there.  Anyway,  since I already own a Netgear 3400 router when he told me this I was very happy to switch modem brands.  Will keep this as an emergency modem but hopefully will never need it.  It sucked up about 6 hours of my life this past 3 weeks.  I gave it 3 stars because it worked okay till it didn't work and I don't think a year is good enough like I said previously.  I don't do a lot of data intensive stuff so whether or not it was slow is not something I would have noticed.  Reliability is what I am after.
3126784
I purchased this modem to replace the rental unit from Comcast. Upon receiving it I contacted Comcast and they were able to register the device with no issues. I've been using this modem for two months and now it has trouble staying online. I initially believed that my older router was the issue, so I purchased a Linksys AC1900 Max Stream EA7500 router. I set up the router hoping the issue would be solved. Unfortunately the internet continued to have interruptions. My streaming devices (computers, Firesticks, and Nest cameras) continued to go down at all hours of the day. I currently have Comcast Blast and had a 91 Mbps download and 12 Mbps download with my old set up. The only conclusion I've come to is that this modem is not what it claims to be. I've passed my return window and now I'm out $70.

My advice is to look elsewhere. I've always had problems with Motorola devices, and this has just confirmed my decision to avoid Motorola all together. I'll be looking at the Arris Surfboard SB6183 for replacement.
746764
Every time the modem gets unplugged or power interruption, it takes forever to figure out how to re-hook to wifi.  The instruction manual has no relation to reality.  It's trial and error balancing an iPad in the dock.  It comes up with nonsensical messages, like "reboot in net link mode" but there is no clear way to reboot except to unplug and start from scratch.

Buy something else.