WARNING: THIS IS A LONG REVIEW, BUT I MAY HAVE SOME ANGLES ON THIS OTHERS DON'T :-) Wow. I really like this modem. This is a barebones rock solid dead simple workhorse. It's got a plug for the cable and one ethernet (RJ-45) port out and I think an on/off switch. That's it. It makes a connection. And hasn't failed since I got it a month or so ago. All I had to do was call my ISP and give them the MAC address (on the sticker on the device) and they updated their tables and that was it. Turn it on. It goes through the startup cycle. Takes a few minutes to connect like they all do and that's it. Set it and forget it. What prompted me to get it, is I don't like having to rent the modem from the ISP @ $10.00/mo forever. This literally pays for itself in 16 months, and most people will have their Internet connection for many times that long, and time flies. So it's a good investment. It doesn't have phone connection like the ISP's modem did. So I called the company/provider that owns copper phone lines in the area and ordered landline service. I'm a nerd/techie and don't care what people say about landlines being for old fogeys, it's like having a backup generator ... I know I can use that landline if the power goes out or if the cell tower gets overwhelmed (too many calls or cell traffic at once), or there's radio interference in the area. Technically cable phone is a 'land line' (hardwired cable connection to provider) and the battery backup in the modem (which the ISP charges more for), could give you emergency phone service in an outage, but a cable phone connection can (and does) fail for more reasons than copper wire phone service does. (Those copper wire connections are called POTS - which stands for Plain Old Telephone Service), and copper wire phones are the most reliable. Having a separate modem from a router is optima for a few of reasons... Generally hybrid units of anything do everything okay, but nothing optimally (for example combination modem-router units like my ISP rents out). Better to keep the modem separate from the router. Then you can swap either out independently to upgrade as needed, disrupting less of your own network configuration doing so, and also help avoid a single point of failure. Plus, you might be able to score a router in a pinch on shorter notice than a cable modem if the router is the component that fails. Then you can choose the router you actually like, for whatever reason, and don't have to settle for whatever bundling du jour your ISP decides is right for you (even if it isn't). That gets me to the other point. What DID the ISP decide was right for me (but wasn't)? For awhile my ISP modem connection was dropping briefly in the middle of the morning. My computer came back up connected to the ISP's 'general public' wi-fi connection to their router which did not work for me and I'd have to keep manually switching back to my own internal Wi-Fi LAN (network). That was not only inconvenient but it forced me to investigate was was going on there. I learned my ISP gives lets passersby connect to their rental-modem's Wi-Fi signal, without giving me any way to disable that service! That really pissed me off to learn. The idea is that people driving around who have accounts with the provider can get internet access around the neighborhoods. If I was a passerby, that could really help me, so at first glance maybe 'why not, be a good samaritan'. But wait! There may be more too it than that. Besides the fact that I don't like it (for good reason), they give me no control over that 'feature'! And I see some downsides. What's good for the ISP isn't necessarily optimal for me. What I don't like about that 'service' is that one or more people could sit outside and suck down bandwidth (e.g. slow my connection down), unbeknownst to me. It also might cause the unit to use more energy and put out a stronger wi-fi signal than it needs to. Which health conscious people are well advised to be aware of. Wi-Fi is radiation. Not strong and may not ruin your life, but it is a stressor at a cellular level, this is known. And strong signals, persistent signals and people who are more sensitive or have immunity issues can be more vulnerable (headaches, sleep disruption, or worse). But I like Wi-Fi so I settle for whatever unknown health consequences I may not be aware of. Also it makes me wonder if a hacker might be able to use it as an additional point of access to my home network. I also wonder if it's 100% clear to law enforcement at first glance who might be visiting sites or doing something nefarious from the connection point. Might it look like the owner is doing something that a passerby did (and even if they can sort it out later, what if it takes awhile to figure out and they make a bad assumption?) Anyway, I don't have that problem with this modem and I'm just much happier with it all the way around. Plus it's blazingly fast.

Received the Motorola DOCSIS 3.1 cable modem on-time from Amazon. Up and running within 15 minutes, No call to Comcast. Motorola Ultra Fast DOCSIS 3.1 Cable Modem, Model MB8600, plus 32x8 DOCSIS 3.0, Certified by Comcast XFINITY Paper instructions were in the box and also online. No firmware available for prior update. I had previously confirmed that this device is acceptable to Comcast. Before buying any network device, always check that your ISP supports the device you plan to buy. Unacceptable for us to rate an item poorly if its is not compatible with your stuff... I replaced a Cisco - Linksys model DPC3008 DOCSIS 3.0 cable modem purchased thru Amazon for $90 exactly five years ago. It has never failed. I would have paid Comcast say $10 / month to lease their inferior modem for the last 60 months, using the roughly $510 savings to enjoy Comcast "Blast" speeds not supported by their leased modem. I viewed this purchase as another future-proof, leading edge decision to replace a 5-year old $90 device. I did not expect a speed increase. Here is why. If I log into my Comcast account and search for upgrades for my Internet service, there is only a fiber option. I am maxed out at a supported wire speed of "150 mbps". I attained that with the 5-year old DOCSIS 3.0 device. So, Comcast does not yet offer DOCSIS 3.1 service here; and, they will not reveal that to customers. I searched for a couple of hours for that revelation. The new MB8600 has a connect LED the turns blue with a 3.1 connection else stays green to confirm 3.0 per the instructions. Mine is green now. So, "NO", Comcast has not brought DOCSIS 3.1 to my area. Follow the instructions. They work. I suggest however that you perform a broadband speed test prior to switching out your old cable modem. I also suggest you have your Comcast account number from a bill and ensure your Comcast account has your current phone number. NOT clearly said; but, I also suggest that you eliminate your network's switches / routers / Wi-Fi and simply Ethernet connect to any one of the four gigabit Ethernet ports on the back of the MB8600. I used port one. The MB8600 synced up with Comcast quickly (according to the lights); but, I could not obtain an Internet connection. I'm guessing Windows 10 Pro simply was trying to protect me from a new intrusion. This is not a Windows 10 / Microsoft Edge issue. Solution: delete all network settings, reboot and there it was, Comcast activate. Enter your data and your MB8600 will reset. Once completed, I was online within 15 minutes. But, the speeds I had before were faster than now. Guess that my firmware had not yet been updated by Comcast. The label on the bottom of the MB8600 has an IP address, user name and password. I logged in and saw that the modem had provisioned to DOCSIS 3.0 with only one channel down and three channels up, far below its capacity in 3.0. You resolve this by pressing in the RESET button on the back of the MB8600 for several seconds till the lights flash. After, I now have 24 channels down and three channels up. I then retested my speeds to confirm that I was exceeding the Comcast Extreme 150 service level I am paying for: 180 mbps down / 24 up. That is a roughly 10% improvement still on DOCSIS 3.0. Again, Comcast here does not seem to support any faster wired speed than 150 mbps, and deeper level of DOCSIS 3.0 than 24X3 and no DOCSIS 3.1, now, no DOCSIS 3.0 32x4 either. I can hope but AOL is perceived as "high tech" here... I hate contacting Comcast customer service since I always feel as if I am training them. I may invest the day it will likely take to get Comcast to remotely re-provision my interface with them. Maybe not. Satisfied that I was connected as well as I could, I then moved on to reconnect my router for its Wi-Fi and more importantly for its added Trend Micro security not offered by the MB8600 since it is not a router, its a cable modem. My configuration is MB8600 to an Asus router with 4 gigabit ports and Wi-Fi AC2400. One wired port feeds a dumb Gigabit switch supporting five devices. A second wired port supports my Microsoft Book. I'm a retired IT guy so I avoid wireless connections excepting my cell. Yes, I have my cable modem, router and PC powered thru an uninterruptable power supply. The MB8600 documentation states that its power supply is resistant to power surges. We have afternoon storms all summer. Its fun to continue surfing while neighbors are dark; yet, my Comcast and DirecTV both work fine with a UPS power supply. Good that Motorola upgraded to some surge protection; but, I want that and sine wave continuous power. For your consideration.... The MB8600 has been connected for roughly six hours. It is barely warm and only at its top. Off to a good start. UPDATE JUL2018: The MB8600 is still running like a champ. No issues. Comcast finally has some competition from Century Link with its fiber optic Gigabit offering wired into my neighborhood just days before hurricane Irma. I signed up for it since its cost was just a minor bump for gigabit from 150 mbps. A few months ago, the green DOCSIS icon turned from green to blue indicating that Comcast had turned on version 3.1 but; I was provisioned for 150 Mbps and did not see a speed jump. Nine months later, still no Century Link offer. Regardless, I opted to move to a different home. Unfortunately an older neighborhood with no Century Link fiber optic. But Comcast does offer Gigabit speed at a higher price. Comcast's cables here are 30 to 40 years old unfortunately. I've been with Comcast for well more than 8 years. This was the first move / install that was completed correctly the first time. The tech clocked 960 Mbps at the MB8600 down. My PC sees less speed (580 to 870 down) with a reliable 40 Mbps up. The MB8600 performs as advertised. All 32 downstream channels and 4 upstream channels are locked.