my midi setup is as follows:

Roland GK2-AH Pickup
Roland GI20 Guitar to Midi Converter
Roland XV2020 Soundmodule (AMAZING!!)

well - that thing works PERFECT. i can play at virtually every speed and complexity and the thing triggers with almost no flubs. some lil flubs are there, but that depends mostly on the settings of certain sounds. with some sounds you can play even sloopy and you wont get any flubs.

however - you need a device to switch between sounds. so you have to get a midi-fotboard.
you can, however, programm the XV2020 so that you have up to 16 different sounds on your guitar depending on where you are. i divided each string into two sections for example: 0-11th fret - sound no.1
12th-24th fret - sound no. 2
that way i have 12 sounds on my guitar to choose from.
you also need a lil expression pedal for stuff like portamento and such. it requires a lil getting used to and a lot of experimental work, but you cna do amazing stuff with it - just listen to what jenniffer batten did when she was touring with jeff beck. that gurl was a whole frigging orchestra!