I knew the name Amcrest meant a quality product, but had never needed to purchase until recently. The item arrived quickly and was easy to set up. I was especially impressed with the amount and clarity of support materials (videos, manuals, spec sheets) available from their web site. But I needed some help with an issue, sent off a support request and had a quick reply from Grace C. That really impressed me as I have had to wait days and even weeks for support from other vendors at times. Amcrest came through for me. Thanks, Grace!This is a great NVR, and the price is also super affordable. I thought it was going to be cheap, because of the price, but surprisingly, it's an awesome. NVR.I have 6 Lorex, 1 Dahua, and 1 Oco camera (all manufactured by Dahua). I had an unused 1.5TB drive that I installed into the NVR. In the 'Events' setup for each camera, I had to set 'Manufacturer' to 'Private.' I was able to set 'Manufacturer' to 'Onvif' for the Dahua and Oco cameras, but if I did, the camera 'Enabled' flag would be reset after a restart, so I left all the cameras on 'Private.' Otherwise, everything in the NVR seemed to work, AFAIK, except I couldn't set the positioning presets. I had to use Google's 'Easy View' for some of the more detailed camera setup.Outside the NVR is a different story. If you try to connect your computer, there is an app for Windows and Mac, but my Mac is too old to try the app. On Linux, the only way to connect to the NVR is with Google's 'Easy Viewer.' It works, but on my quad 2.2GHz computer, it uses 40-50% of the 4 CPU's time to operate. These choices were unacceptable for me, so if you are running Linux, and want to connect your computer to the NVR, I can't recommend it.Either Android or iOs can run the 'AmcrestView Pro' app that can access your NVR from anywhere. It basically works, AFAIK.I bought this to use it to offload the work of processing the camera data, but the Ivideon software running on my Debian computer is more efficient, so I'll have to continue using the Ivideon software. However, the NVR is recording *continously*, as well as recording events. Our neighborhood had the mailboxes broken into a year ago, and since the Ivideon software is set to only record events (for lack of space), I got a blurry image of the car in one event, and the broken mailbox without the car in another. So, I think having a continous recording makes the NVR worth having.One last observation. My Debian machine backs up all the Ivideon camera files to rsync.net each minute, so if someone were to break into my home and steal the electronics, I could still recover the Ivideon files and examine what happened. So far, I don't see how that can be done with this NVR.Bottom line: for me, it was worth buying just for the continous recording capability. If I see something in the Ivideon events, I can go back on the NVR and see the before and after video.Easy to connect, a bit of a learning curve to the interface, but that is to be expected with a customizable setup like this. Lots of options for recording times and such. You can also use motion detection to search through the footage and pick out areas of the screen to detect motion. One thing to note when setting up your camera, it is important to set your IP to "static." Otherwise the NVR and camera will lose connection sometimes. Trust me, I learned this the hard way.Customer service is excellent. I had to contact on one occasion due to an issue with the app (turned out to be caused by an updated to my phone). They responded quickly and had it fixed in less than 12 hours!One negative to this unit is occasionally I will get a vibration sound through the case from the hard drive. I think I have remedied it by using painters tape and other methods to make the fit a bit more snug and dampen vibrations. Not a huge deal, but a minor annoyance.I really like this nvr for the price but I haven't been able to get the remote viewing to work so far. I had no problem connecting my Hikvision and LTS Security branded cameras to the nvr. I use a 32 inch tv for viewing the cameras and I've tried all of the resolution settings and part of the image "runs" off of the screen. If my power goes out some times the cameras won't reconnect to the nvr until I refresh the cameras in the nvr settings. I've tried to setup the remote web browser viewer on my pc and still have not been able to get it to work based on the instructions in the manual that came with the nvr. You're supposed to scan a QR code with your phone to do it but it doesn't work. I tried another method on the manual by entering my nvr ip address and it takes me to screen asking for my nvr login. I enter my login credentials and nothing works that way either. Works great for recording and viewing on the screen connected to the nvr but don't count on getting the remote viewing to work.The NVR itself works great. App needs improvement.The NVR works with other brands of cameras using ONVIF without any issue, it also supports camera from its own brand well. It is quiet (no fan) and easy to set up.The Amcrest iOS app needs some improvements, eg:* it is difficult to playback, you can’t play back from the live view screen, you have to jump to the menu and go to the other screen, choose camera you want to playback and play. It is just too many steps for such commonly used functionality, and the camera chosen in the playback is not remembered. It means you need to choose every time you want to playback. The UI is worse than the other NVR I have.* the aspect ratio is off in both portrait and landscape phone orientation which caused distortion when viewing the video. It should keep the aspect ratio and fill the rest with black screen instead of scratching it.It would be 5 star without the poor app experience.I've been disconnected with multiple Tech support. First with Selena, who promised to call back in 10 minutes. Never did. Spoke to another Tech who said would arrange a call back, still haven't heard back. Today speaking with Jessie, the phone got disconnected twice while troubleshooting and even after giving them access via remote support, no attempt to reconnect with me.Will return this NVR and HD if they do not return my call.Was delivered 3 days after I made my orderGreat company (Canadian)Excellent!