To be honest, I’m actually rather uncertain about what to do with these UAD plug-in sales. They used to be really expensive and linked to hardware, but where are they going now? $29? $19? $9?
It’s pretty weird. And one of their head honchos has gone over to Apple. Strange days.
For cello playability (with piano) I would definitely prefer the Bohemian Cello from Virharmonic, Emotional Cello from Harmonic Subtones, or even Tina Guo from Cinesamples, although the latter admittedly is quite creative.