Pirastro = White meat
Jargar Superior/Larsen Magnacore = Dark meat
I just swapped my Jargar Superior A & D + Larsen Magnacore G & C for a full set of Pirastro Perpetual soloists.
I find the Pirastros to have a brighter sound with less growl and more overtones. On my cello, they sound a little thin and fizzy.
The Jargar/Magnacore combo had a more distinct throaty voice. And there was not a single moment where I didn't absolutely love the Superior A. I can't say the same for the Perpetuals, unfortunately.
Response was a little stiffer on the Pirastros, but resonance was better. Power and volume were about the same on both sets.
In my opinion, Perpetuals do best on darker instruments or instruments that need a little sizzle on the top. Magnacores (I will hazard to say full set) will do better on a brighter instrument with a more neutral color.
Have a video for comparison