the tracking of the guitar synth using the gk series pickup is not as bad as what some would say. It is actually quite decent. Some patches are more sensitive to ghost note though. A lot of it also depend on playing technique. The guitar synth wont tolerate sloppy fretting/picking habit.
Beside the axxon stuff, another way is to get a brian moore guitar which has the 13pins rmc system.
If not, the gk 2A or the latest one, gk 3, is decent enough...
The latest offering of the guitar synth is the gr-20, a simplifed and improved version of the gr-33.
If you want something that has the guitar synth plus the rest of boss COSM technology, VG-88 is the one to check out.