Some of Arturia's newer emulations sound pretty darn good to me (DX, CZ, Buchla, Synthi), but that OB-Xa did not. I know you test for them or do sound design (or both), but I have no pony in this race, nor am I an Arturia basher or big Synapse fanboy (I only own The Legend compared to a million Arturia products hardware and software). That OB-Xa V was just not "good" to my ear. It just made me appreciate the filter of the OB-Xd, which isn't even some fancy circuit modeled emulation as far as I know.
So either the OB-Xa hardware sounds bad [to me] and Arturia nailed it, or the emulation wasn't very good. I've heard some terrific sounding YouTube clips, so I'm thinking it's not the hardware that sounds bad. I'm waiting for Synapse.