I recently bought a Roland GI-20 guitar to midi/USB interface. Alas they don't make them anymore. Tracking as good as it gets with the Roland GK system. You could try a Godin guitar with the 13 pin output, they use piezo pickups. They claim improved tracking.
Waaayyyy back i had a Casio Midi guitar, way cool in the 1980s but the midi tracking had some latency. Older Roland GS like GR-20 and even GR-1 have a good tracking for the internal sounds but a little latency on the midi output.
Waaayyy back i used Atari computers with the built-in midi ports, excellent timing.
I wrote a post here about the USB in of the Kemper. I wish i could connect my Gr-55 or GI-20 USB out to that port and work with the GK hex pickup. Alternate tunings, different FX on different strings etc.