I have a Godin LGXT electric guitar and a Roland GR-55 guitar synth. It can output midi, too. Although it is usable, I wouldn't even try to use it as an input device for notation. It requires constant concentration on clean and pure playing. The small failures, although not always critical in playing would certainly confuse a notation software and you would spend more time correcting the errors than it would take to enter the notes other ways.
At one point I had a small Korg Nanokeys keyboard and a Korg nanopads. I used the nanopads to select correct note values and the keyboard to enter the notes. After some practice it was actually quite fast way to enter the notes. With Sibelius, the use of the nanopads required some xml file editing, though.
Learn Finnish, part 1:
ice-cream cornet: jäätelötötterö