That's a Dahua DVR. They are the manufacturer for a lot of US dvr brands like Mace, Intellicam to name a couple. Many more though.
Very good system. I just bought one a little while ago and I love it. I bought directly from China, got a 16 channel for $480 including shipping, has a 1TB HDD, apps for iphone, android, blackberry and a windows phone in the works. They are constantly updating the firmware, which is key to me, i'd rather buy from a company that upgrades firmware rather than just making newer systems. It can record to the internal HDD and a NAS device at the same time (also key for me, I have a vpn set up to an off sight NAS so it records to both), they also have a program to automatically backup to any other pc or NAS, I think it will only do a day behind though, still playing with that.
Obviously, all the "normals", record on motion or alarm etc.
Not very fond the web based access, you have to shut down all the security since they're active-x (I think?) isn't signed, but they have an app called PSS (professional Surveillance System) that works great and you can access all of the config from it. I asked if I could add a panasonic camera to PSS and they said not yet so I'm hoping soon I can have all my cameras in that one program.
The downfall is the language. Some things you'll have to try to interpret what they mean because it's "broken english" but they have a support "forum" (not really a forum) that you can ask a question that gets posted on their site and they will answer it in a day or two. No replies over the weekend but they do answer every question.
So that's probably a bit steep pricewise for a 4 channel but it is a good DVR.
BTW, www.dahuasecurity.com is their site