I recently added a Raspberry Pi 4 kit from Labists to my collection. The kit includes the latest Pi board, case, fan, cables, and microSD card with the OS. The instructions for the kit are pretty sparse, but the assembly was relatively simple to figure out. It only took 4 screws to mount the board to the base of the case and 4 screws for the fan. I did have to Google how to connect the fan. The Pi 4 will throttle the CPU if the temperature rises too high so I ran my little Pi with and without the fan. I was not able to detect that much of a difference with my highly unscientific experiment. Of course, I wasn't really pushing the hardware.
Labists preloaded NOOBS, which is the OS installer for Raspbian. I did have a few spare 64GB cards laying around so I did some quick tests with other distros. I was able to bring up Ubuntu Server, but I did not have much luck with any Fedora releases for the Pi. I'm going to run with the Raspbian release for a while since it does fully support the entire hardware platform. I'll switch to one of my preferred Linux distro once I'm more familiar with the hardware under a fully supported OS.
I don't have a project lined up yet for the hardware. I have seen several posts about turning them into mini file servers; however, that really doesn't seem like much of a stretch for the hardware. Besides, I have an old Asus Eee PC filling that role. The Labists case does have hole in the cover for a Pi camera and a 1/4-20 screw threading for a camera mount so I may try some sort of image capture project.
I'm fairly impressed with the hardware so far. My only challenge will be setting aside time to tinker.