Thank you for the review Mike. Most particularly, thank you for the fan mod information.
I have the faster N40L model of this microserver at home, and have had it for over a year now. I love it, my only complaint is the noise level being a bit high. I had suspected the small fan on the power supply. Now I have guidance on curing this.
A few extra things that might help: For those that will run FreeNAS; that OS boots off a USB stick, and there is an internal USB socket right at the front of the motherboard. That means this stick is inside the locked front cover, out of harm's way, and away from tampering. I have run mine up with a 4TB Hitachi drive. Not that I would recommend that drive. It was installed as an experiment, as it was going into a different machine. But they work. I only run the listed maximum of 8GB memory, but apparently they will support 16GB - at least.
For those who want to use these machines in a business setting, and a friend of mine does (the even later N54L), I suggest the Remote Management board - web access to the machine is much more than a useful addition. If you do add one, note that the normal VGA outlet is replaced by the one on that card - this caught him out. That HP also offer on-site support contracts (well they do here in Australia), is another huge benefit.