Sterile yes, sometimes, but on the other hand this sampled vibrato sounds very natural (only repetitive in the long term), whereas the modeled vibrato of Roland SN-A tones generally sounds artificial, as the modeled oscillations of pitch, filters etc.are just not the real thing.
I think this is one of the things Yamaha SA2 sounds a comparable technollogy to Roland SN/A does a lot better...
Ketron sounds deffinately good with the sampled effects in the sound, tough is less flexible compared to the SN/a, DNC and SA sounds....