I already had an old Motorola @ 15 Mbps .. moving to @ 75 Mbps really easy.

Does not have the puma 6 chipset which drops signal and has major latency issues. Is why I bought it and works like a charm with a good router. 5 stars

I decided to upgrade my entire network once my Cisco modem started glitching out. The Motorola SB6141 looked to be the best on the market at the time so I added it onto my network and paired it with the new NetGear "NightHawk" R7000. Setup was quick and easy through Comcast with only one call.Note to buyers: the black ones are for non-consumers/businesses so they're all used pretty much, but mine came with all accessories and had no sign of use. I believe the firmware shipouts have been fixed or Comcast auto-updated my firmware without my knowledge since mine was black and came with 1.0.6.10 instead of the bugged 1.0.6.3 firmware. The bugged firmware most likely caused a lot of returns which is why they're able to sell these to consumers.Testing out the speeds I was able to crank out about 60mbps on what is supposed to be a 50mbps connection after configuring things (I have a super strong signal coming from my isp, just enough so that it doesn't cause connections issues.) So far after a few months there have been no dropouts or slow down like with my old Cisco modem. Everything I download maxes out speeds and is finished within seconds if under 1GB.The modem is open-sourced, but the configuration page (if you can call it that) leaves something to be desired. On mine I can't change the modem specific settings, it just gives me what its set to. On my old Cisco I could change quite a bit concerning signals and such. I'm assuming there's another device to be paired with it that enables the changing of settings. So to be safe I'd reset to factory defaults (the only thing it allows) in-case someone was able to access settings and changed things.Overall a great top of the line modem, built to handle everything except Google's insane fiberwire connection. Right now I'd say it's king of the hill for those without Google.

I wanted to buy my own hardware & avoid the Comcast $8/ month modem lease fee (which just went up $1 from $7/ month). Lucky for me, I received this today & my billing cycle starts tomorrow. I called them up, got the address of where to drop off the leased one, & registered this one to avoid the $8/ month BS.I unpackaged it, let it thaw out for a few minutes, then fired it up. It works really well with the Netgear Wireless N Router I also bought off Amazon last week. That thing was ~$25. This was ~$80. This Mototola modem is conveniently MUCH smaller that that behemoth Comcast left at my house when they installed my stuff a few months ago. Regardless, I hid it behind my big bookshelf style entertainment center. In the end, though, I'd still prefer to have my own small modem & my own router rather than a giant p.o.s. box Comcast is charging me $8 a month for.After plugging everything in real quick, I launched a Firefox window & it brought up the Comcast self-install page. I quickly entered my account # & cell # registered to my account. I was prompted to click "Next" a few times, etc. It was up & running w/o calling Comcast w/in 5 minutes. I called Comcast anyway to find out where the closest drop-off location was for the old one. At that point, the guy on the phone requested the serial # of the bottom so they can register it in their files. I was kinda debating giving it to him, but they already have the MAC address of it w/o me telling them & I'm pretty sure I can unregister the modem in the future if I plan on turning around & selling it to a different Comcast customer.***I had come across reviews where other Amazon shoppers complained that if one specific modem is registered in the Comcast system, they will not allow the same modem to be used with a different customer's account. This may not apply if the person who it's registered to calls & unregisters it. I'm pretty sure it works the same way like with how cell phone providers deal with lost/ stolen phones if someone buys one off the web & wants to use it & it's on that specific carrier's black list.It's a big, giant, pain in the ass & if that's the case, I'll list it as "No Comcast" or put something in the description like how people on eBay put "Bad ESN" when selling such a phone. If that is the case...This modem supports up to 300 Mb/s so I don't anticipate having to try to sell it anytime soon.WIth the Comcast giant box, bandwidth test download speeds were ~17 mb/s (I'm supposed to have the Blast! service. I thought that was supposed to be ~50 mb/s, but I could be wrong.) With the new hardware, it was closer to ~25 mb/s. A nice improvement.So, all in all, I really like this modem so far & would recommend it to anyone looking to avoid those pesky modem lease fees. Also, I could not get my network to work right with the leased Comcast equipment. I logged into the device settings with 127.0.0.1 or whatever the device address is. I changed the network name & password to whatever I wanted. It worked for just that time. The next time I opened my laptop, I was not connected to the network. All the settings on my computer network settings for the newly named network were correct, it would just not work right. So I reset everything back to default & tried again & changed JUST the password. Again, it worked just for that time then ceased to connect normally & automatically after that. EVEN after insuring the network name, type, security key, etc. were ALL correct. I dunno, I wasn't too comfortable with not being able to configure my own home network w/o such a nightmare or w/o having to call their customer service. I wanna pick my own network name & password... I've set-up 3-4 wireless routers in the past, something was not right with the Comcast one.So I went with this modem + a kick ass Netgear Wireless N. Very happy :)