This is a nice single board computer in a small fanless heatsink case. It doesn't get even warm to the touch when operating, very low power. I spent some time with the CasaOS that came pre-installed. Its got some promise, but in my opinion not quite ready for my application. I've been using Open Media Vault for several years on a much older nettop computer with excellent results so I installed it instead. OMV 6.0 installed in minutes with no hiccups at all. This is not to say that CasaOS won't be a good choice in the long run, it's, its got good potential, but its still a 0.3 release. OMV has full docker support available so it can run most of the applications that make up CasaOS, but docker isn't required for the core functions.
The ZimaBoard hardware is really nice. You could get one of the low powered micro NUC like packages with a Celeron processor in the same price range and have more CPU horsepower, but it will be missing the PCIe slot, the second GbE port, and probably one or both SATA ports. If you look at Raspberry Pi you end up needing a case, plus multiple shield cards to get the GbE and other basic ports. The ZimaBoard doesn't need any other cards for most applications. It loads software very easily, you just need to know to use F2 on boot to get into the BIOS to boot from a USB installation stick.
I'm still assembling my server. I'm planning on two 5 TB 2.5" USB portable disks for the primary file storage, and another pair of 3.5" large disks for backup and media files. I'll use an external power supply for the 3.5" disks along with the SATA interfaces. I like to use the USB disks for general file storage, (along with NTFS file system) so I can just unplug them and move to a PC to recover or copy data if there's an issue with the server hardware (I've never had to do this though). I'm not planning on using the PCIe slot, although it might useful in the future. If you wanted an all SATA server it would be cool to use for a multiple port SATA I/O card. I wish they offered a bracket of some sort to physically mount the ZimaBoard plus mount for the PCIe card. I could make this, but it would be much cleaner and professional to have a manufactured solution.
The ZimaBoard has some real advantages over alternative platforms for either file servers or firewall use:
1. Dual GbE ports onboard.
2. Intel platform with good compatibility with any Linux based OS
3. Dual SATA onboard
4. PCIe
5. Very low power
Things to consider:
1. The CPU is a pretty old generation, although more than powerful enough for router or file server duty
2. While nicely packaged, the PCIe slot needs some fussy mechanicals if you want a securely mounted card
3. The SATA ports have only one power connector, and doesn't support enough power for 3.5" disks
4. Not enough horsepower to run Windows, especially server.
If you don't mind a bit of tinkering this is a great way to put together a NAS or gateway router, really not much more work than an off the shelf NAS box, but much less expensive.