I totally understand picking a bjj black belt as an instructor over a tpjj purple, that happens alot.
If it's pure no-gi you want I would suggest the tpjj purple without a doubt.
But if it's a mixture of gi and no-gi that you want and the bjj black belt has at least 2 nogi classes a week, then maybe the bjj black is a better fit for you.
But if the bjj black belt is not open minded to the rg, twister, and lockdown half then for sure run from him. Closed minded black belt instructors are sometimes worse than white belt instructors
And thank you very much Eric Perez for the hardcore loyalty to 10th Planet, that's never a bad thing