Just make sure it supports Ivy Bridge out of the box if you're going 3225. Does seem like a faster option than the NUC, though at a bigger size and larger power draw. Shuttle at least used to be the king of those little SFF boxes. They seem to have been marginalized by mITX motherboards with fancy features and small, decent mITX cases. I haven't read a review of a Shuttle box in a long time, though as long as the quality hasn't dropped off it should be good enough. The i3 3225 is a pretty speed chip for a cool and quiet box.
The most recent SFF experience I have is with a Biostar iDEQ 200N, which was an nForce 2 system that I paired with a GeForce 5700. Pretty sweet little box for the time, though not really indicative of the current market.
I do not understand what I do. For what I want to do, I do not do. But what I hate, I do.