Sorry if my english is approximative.
I use my Parva with an old but exelent converter: terratec axon ax 100 mk2, with sensors piedzo + expander “ghost”, by graphtech, on my guitar. After long searches it did appears like the best.
I confirm that the sensors graphtech are very much better than the roland system, more accurate, and very better for to play with finger. The terratech also, more accurate than roland systems, with less latence, with various settings of sensibility and with possibilities that no exist in others material. It don’t work with MPE but with one channel for each string I have a very good restitution of playing, with bends and all sensitivity. Terrific! But I had to take a lot of time for to find perfect settings.
BUT, two problems, who were worst with roland: There is still a little bit latence, not pleasant. Especially when I play fast rythmic sequences. For exemple it’s difficult to keep tempo in fast arpeggios for a long time. And sometime short unwanted notes can appears if I don’t play cleanly.
I still wait for the perfect system.
I don’t think that the fishman is better (but better price!), I did read that had also latence, and I have more confiance in piezo sensors.
If You try it I would be grateful to know it.