Thanks Rob, real life experience is really useful.

Benchmarks I am reading are not too comforting.
For example: http://www.storagereview.com/drobo_5d_review

The thing is, with a NUC being the brain of the system, a Drobo (or any competitior) would not be just storage, but also host part of the system files. Not much because of storage size (mSATA these days are up to 250GB at relatively low price), but because I'd definitely want to have them on a hardware-redundant storage.