That's not surprising. I have a few Vitek cameras for a few random, low priority things that I'm pretty sure are re-branded Dahuas.
Something to keep in mind though, as the number of pixels go up, the nighttime sensitivity tends to go down. My 4MP Speco cameras are noticeably darker at night than the previous 1080p cameras I had. The exception to that being the Dahua varifocal camera I have (which I believe uses the same image sensor as the Speco cameras). That one has pretty good nighttime illumination, however, the IR is set up quite a bit differently than the Speco cameras, so that probably plays into it.
The outlier there though is the Starlight+ cameras - their IR sensitivity is great, and the image is far crisper than 'regular' 4MP IR, due to the sensor being much bigger and also of a different overall design. My regular 4MP Dahua varifocal looks good during the day, but at night, it gets a little fuzzy, which is something I've seen in nearly all cameras. But the Starlight+ varifocal, which is overlooking the same area from a different angle, is far crisper than the regular one. You can make out individual blades of grass far better than the other one. And like I said, the Starlight+ cameras light sensitivity is outstanding. I can look out my window and it looks almost pitch black, but look at the camera and it looks like daytime. The low light color is NOTHING like the Speco Intensifier that looks great with a static image but if something moves across it, it looks like a ghost. If you have one or more areas that have a decent, constant source of illumination, the night color cameras are really nice. In my case, I don't have enough illumination, so they won't work for me, which is why I went with the Starlight+ as it's pretty much the same camera but with the addition of IR.
The camera you linked has a sensor that appears to be the same size as the Sony StarVis sensors found in the Starlight+ cameras, but being it's 4k, I don't know if it is a StarVis sensor or not.
Just my opinion here, but while I'm sure 4k is great, 4MP cameras are quite good - especially the StarVis equipped Starlight+ cameras. My current 4MP cameras are leaps and bounds ahead of the old 720TVL coax cameras I originally had
. If someone were to give me some 4k cameras, I'd give them a whirl, and might even like them, but to be totally honest, for my intended purposes, the 4MP cameras give plenty of image quality. If I were to go out and replace any of my cameras, I'd replace my Speco O4D1's with Dahua N45DM62. The cameras I have in use are Speco O4D1's, Dahua N45DM62, Dahua N44BN52, Dahua N45DL7Z and Dahua N45CL5Z.
As far as BluIris, I'm personally quite happy with it. I like the alerting capability and the overall flexibility. It's FAR more flexible than any DVR or NVR I've ever used. It does need a fairly beefy machine to run it though. But it does blow my mind that a NVR running most likely an Atom CPU can run 32 channels of 4MP at 30FPS without issue, but BI needs quite a beefy system. I have 14 cameras all at 4MP, and some at 30FPS and the rest at 15FPS (for most cases, you really don't need to be running more then 15FPS). My BI is running on a PowerEdge FC630 with 14 cores of a E5-2699v3 enabled and it runs at around 25% CPU usage. One thing someone mentioned about decoding and re-encoding to save to disc - You can enable direct to disc and it'll just stream the video right to the disk and the decoding that's done is just for motion analysis. You can reduce the CPU usage if you have a machine with Intel QuickSync or the NVidia counterpart, but when I experimented with it, I wasn't overly impressed. It reduced the CPU usage some, but I also had some quality issues with it. And I believe if you're just straight recording all the time and recording straight to disk with no motion analysis, that would probably also reduce CPU usage.
