About a year ago I got myself a NUC. This thing has been running my home server for all this time, and i got nothing but praise for it.
First of all, the box is quite well made. They got this sensor installed that makes that famous "Intel" sound when you open the box. Nice touch, Intel! The NUC itself (i got the Haswell i5 one, the most expensive at the time) is a bit on the heavy side, i expected it to be lighter. But then again it's mostly metal, and the NUC feels quite sturdy and extremely well made. So i got no complaints there - everything is where it's supposed to be, nothing loose, nothing broken. Nice.
The hardware is quite capable - i have never run into anything that made me wish that i had a more powerful box, and i've done it all - transcode DVD's, running ZFS RAIDZ, web server (for a while), you name it - i dun it. And it's quiet too. And having SSD as system drive is very nice - updating to the next version of Ubuntu took about 10 minutes, most of which was downloading the stuff.
One minor point is that for some reason they decided to go with mini-HDMI, which i burnt myself on. But this is indeed a minor point.
I do have a few words for Ubuntu though. Stop fucking changing around udev device names, dammit! I'm fucking tired of bringing up my ZFS cluster after every update-induced reboot! Assholes!
P.S. Pretty soon Ubuntu will be at codename starting with W. I hope they choose Wanking Walrus as a codename.