Good for quiet and limited power draw applications.
Horses for courses. I've been a computer guy since the 1960's (PDP-8), and have been living off the grid (solar) since around 1980. I thus care a lot about how much power something uses, especially if it's on much of the time. I have 3 Haswell i5 nucs here (along with some other machines) and yes, while expensive, you do get what you pay for - rock solid reliability, super low power, very very quiet and small.
They seem as fast as another system I built in the standard tower case with 2400 mhz memory and an Nvidia 4 monitor vid card (which isn't for gaming, but stock trading). If not a little bit faster.
They are more or less silent unless really loaded up with say, rendering video, when you can hear them a little in a quiet room, at least the tall ones I've added 1 or 2 terabyte spinning rust to - those do get warmer.
I do like putting them on the back of monitors. All but one of them drive two monitors here (often using adapter cables for older monitors). In many ways, they are the nicest computers I own at *any* price in speed, quietness, and reliability. There were some initial glitches re UEFI and some linux distros - all fixed now. Till further notice, any more desktop computers for this campus will be NUCs.
Compared to the only other machines I could leave on 24/7 - everything else is a joke (eg raspberry pi model 2 or some android). Yes, they are expensive, especially if you get the best ram and disk. You get what you pay for. Get a powered USB-3 hub if you're going to build one out...
Biting the hand that feeds IT
