I'd like to see other reply's to this question!
I have a GK-2A & GR-1 hooked up to Cubase VST 4.1 Mac.
It shows up the same as a keyboard (sort of) I always experience little blips (tiny 32 or 64th notes added with every note) so I have to edit all those blips out.
[time consuming]
Slide guitar? Probably do able but it won't be easy and effortless with out much editting.
I found the USB interfaces make the tracking a little quicker.
And most important advise for midi guitarists is try a set of pure nickel strings.