Pros: Purchased at the end of 2013! Running 24/7 it's still running strong 4+ years later. See note below about the fan.

Cons: Fan not only loud but died around the 3 year mark, causing overheating shutdowns. The fan was easy to replace and the system was not damaged, is still running strong!

Other Thoughts: I recommend preemptively replacing the fan. When I first bought this it was one of kind, particularly at this price. But now years later (2018) you can get comparable faster multicore systems, with more NIC ports. But with those systems you're gambling on the longevity. If the system specs are good enough for your use, then I still think the tried and true nature makes this a smart purchase.

Pros: - Reliable
- Quiet

Cons: - None

Other Thoughts: I've installed both pfSense and Sophos UTM. It handles both with no issues. It has never crashed on me. It just simply works.

Pros: 1. Good value for the price
2. Installed pfsense and worked fine for my DIY router.

Cons: Fan is a bit loud.

Other Thoughts: My internet connection got upgraded to gigabit (Cox) but the processor is unable to keep up. Can only get 400 mbps throughput. So look else where if this matches your usecase.

Pros: amazing price
2 gigabit ethernet ports (Broadcom [bge])
2 SATA ports
small

Cons: loud CPU fan - I easily replaced it with a quiet 40mm fan
video resolution - it took some fiddling with 'xrandr' in Linux to get it to display at my monitor's native 1600 x 1200 resolution
flimsy backpanel - there is a ton of flex when connecting cables - the rest of the enclosure is rock-solid

Other Thoughts: Operating Systems Tested (all worked): Linux (Ubuntu & Trisquel), OpenBSD, FreeBSD

Included items:
- enclosure
- motherboard
- CPU + fan
- cables

Stuff you need to buy:
- hdd (2.5" only)
- memory

Not tested:
- HDMI output
- dual monitor configuration
- audio
- USB3 ports

Closing thoughts:
This computer is not meant to replace your workstation. Instead, it is a valuable machine that can be used for OS testing, router, firewall, server, SpinRite, etc.

* * * * * UPDATE (November 7, 2017) * * * * *

This computer has been running without a hiccup for me. I have loaded it up with OpenBSD and it has been serving as my home router since August, 2013 ...over four years!!! Amazing!

Pros: -Room for 8GB of memory! (although the manufacturer only recommends a max of 4 it still seems to read up to 8 with no problems)
-2 SATA ports for lots of storage
-USB 3.0 (apparently)
-Nice overall design and lots of ports

Cons: -Chassis only has room for one hdd
-Really bad display issues (see below)

Other Thoughts: I got this system to replace another barebones box that I was using to run a Debian web server. First I tried swapping in the hard drive from the old system- this worked perfectly except for the fact that the OS was not detecting the ethernet ports, something which I couldn't fix despite attempting some configuration. I expected this as swapping HDDs between systems with different hardware rarely works without any hitches. However, next when I tried installing Debian to a fresh drive, the system would not display through either the VGA or HDMI ports after installation. I could not even get a command line to display. This problem persisted with install attempts of CentOS and Ubuntu. It's a really strange issue since since GRUB shows up normally on boot and also that the original Debian HDD worked fine, however since there really doesn't seem to be any way to avoid it when doing a fresh install of the OS, this box is pretty much a paper weight for me right now. I will be requesting a replacement and hoping for the best.

Pros: Fairly priced, runs most OS okay

Cons: doesn't do anything well. I think the it's the processor, but the performance lag even as a pfsense router is big enough that it gets used as a test system

Other Thoughts: It's a fair price but the hardware isn't that great. I ran it with a bunch of operating systems with a 256GB SSD. Pfsense, Kali, win 7, debian. There was enough of a performance issue that I chucked it. I have an old dell poweredge server running a bunch of virtualized pfsense OS (the processors on the poweredge server are better but ram, hd, nics are better on the MxPC

Pros: Small with dual nics.
Perfect for my Untangle setup

Cons: None

Other Thoughts: This was a purchased for a custom build for an Untangle system. I put in a 120 GB SSD and 8GB of ram and it all worked out really well. I am very happy with this install.

Pros: - Good price
- Small form factor

Cons: - Noisy fan (not huge deal for me as I have it sitting in a utility room)
- Nuisance to boot from USB

Other Thoughts: As some other reviewers mentioned, it's difficult to get the product to boot up from a USB drive. Couple tips: a) use the USB 2.0 ports and not the 3.0; b) there is a boot override menu in the Save/Exit menu of the BIOS to select / force to boot from a specific drive. I was able to use this vs. specifying a boot order to give the USB drive priority (which didn't work) to get the computer to boot from the USB stick.

pfSense runs without issues (at least the first few days).