I bought this to run PFSense on and it works well. I was able to boot up, install and get going fast. I do not have wireless installed so I cannot report on how well wifi works, but as it is cabled, its great. It does everything I need to and is plenty of fast for a firewall.

The only issue i have is it does not seem to have a wake on power or wake on network function, so if you lose power to it, you will have to manually press the power button to turn it back on. This isnt a big issue for me as I have mine on a UPC and it boots fast, but there have been a few times I have lost power and the UPC ran out as well.

This equipment has been with me for almost 2 years and did not have any issues. It has been great and my current home perimeter router/FW. I have learn a lot about those kind of appliances. Super reliable.

Runs OPNsense with AdGuard Home and Zenarmor without any issues and plenty of headroom to spare. The CPU cores float between 46-49 degrees Celsius mounted in a mostly gutted cable distribution box with the cover on.
Be aware that this will probably require a 15-pin VGA connection to set up initially.

This computer is more than enough to run ipFire, OPNsense or pfSense in a small network environment. The M.2 SSD inside makes booting and configuration changes a snap. I had no troubles booting from USB thumb drives to test and compare IPfire, Opensense and pfSense software, and no troubles using the VGA output port to an attached monitor. Each of the three routing software packages I tried had no difficulty recognizing the hardware of this device. I had no trouble implementing VLANs, booting, shutting down, updating, or assigning interfaces.

Layout-wise, it is awkward that the power supply plugs into the front of the device to the left of the four RJ-45 sockets instead of in the back.It would be nice if the power button on the back would be on the front instead of the back too.

In operation with packet-filtering and port isolation on three ports and a WAN port, with a fair number of traffic shaping rules, the case gets warm but not hot to the touch (so far). For a larger network than mine that only has a couple dozen computers connected at any time, and only a few doing much at a time, I would opt to get a two port version of this device so that this could be a rules based firewall and then leave the rest to a good quality network switch.

Using this as an all-in-one firewall / routing device behind a home or small business Internet bridge is only marginally more capable in some ways than a less expensive and faster Mikrotik router / switch type unit. The balance between the two approaches is that the Mikrotik RouterOS is extremely efficient but more difficult to configure in a hybrid bridge / switch configuration, whereas pfSense and this device is approachable. Lately, neither this computer and pfSense or the new version of RouterOS are well documented, so plan on spending some time testing your results if you go down this path. It is unlikely that most configurations will make good use of the 4th ethernet connection, but it is nice to have. If you are an experienced and patient engineer type, a Mikrotik (especially models with a built in switch chip) would probably be more efficient and much less expensive.

I am skeptical about the product ability to handle a lot of active rules and connections without some overheating, however this hardware was able to handle every configuration I threw at it with ease.

I wanted to escape the toil of working through the new Mikrotik bridge / switch approach in RouterOS, and did so, but it probably took me as long or longer to come up with a working approach for my needs using pfSense and this device. Sometimes, it really is just so much easier to use two or even three simple device / logic combinations instead of trying to fit everything into a single unit -- the allure of using this computer.

Caveats:

Having the monitor port and usb sockets for configuration was really luxurious. A couple configurations would have locked me out without them. BUT - unless the "Windows 7" legacy boot mode is selected in BIOS, there must be a monitor or dummy VGA plug connected to the device for it to boot. This caused some head scratching when I carried the pre-configured unit to the computer room only to find it unable to boot headless there. Switching the BIOS to the legacy Windows 7 mode took care of it without loss of configuration.

Watch out for pfSense configurations and add-ons. Some add-ons (thinking GeoIP related) ended up bypassing the firewall rules, thus had to be removed. Also, some settings are not applied without a full reboot of the router, even though the interface reports that all has happened -- be sure to test things and include a reboot every once in while to be sure that everything works as planned.

This is such an expensive device for what it ends up doing, it is tough to justify having a spare. I'm keeping a less expensive router within reach to fill in for this unit in case it fails early..

If it turns out that future setups take me back more into Cisco or Mikrotik, repurposing this computer will be tough. The model I bought has no HDMI output or 4K video, no sound, and no Thunderbolt 3 ports, yet its M.2 drive and CPU / Mainboard are quite peppy. It will be a sad waste of money to toss it in the e-waste box for lack of a future use path.

End User Verdict after One Month:

This is a keeper, hardware is enough to have a luxurious router / firewall toy that works really well so far for home and small business. More ports than needed for a firewall router, as the other ports will be bridged, but workable with various rules. Ideally, this unit with an HDMI receptacle and two, or three ethernet ports would be fine if coupled with one more separate switch units for most uses.

If there are product issues in the first year or two, I will update this review to reflect those issues.

Got this little thing for pfsense and its great - get the wireless one but this is over kill for the basic firewall needs.