I recently picked up a Sarno Black Box and gigged with it last night with Ronnie Penque of NRPS. It sounded great! The best I can describe is that it gave me a silky smooth glassy sound, even at higher volumes, something I have found difficult to achieve.
My rig was: guitar -> Sarno Black Box -> custom built external vintage Ibanez pre-amp/EQ -> Roland JC77 (2x10 solidstate amp).
So, a double thumbs up from a 'Bobby' in the crowd.