I have Roland GK3 Guitar synth pickups on both my Gibsons.
I use them with the Roland GR33 guitar synth.
The GR33 is a very good synth and the GK3 tracks very well.

The sounds in the GR33 are a different matter.
Many are gimmicky and useless apart from being used for ambience between songs, a la Steve Miller. I was totally astounded that the old General Midi stalwart Vibe patches are NOT included as standard fare.

My web research came up with the following link as being the most useful, even if most of the patches were put on site years ago. Not only do I now have Vibes, but bagpipes as well, and a very good banjo sound.

I use a Edirol USB midi port to connect the GR33 to my computer, and use the Grapelight patch editor to download patches back into the synth. The comments about problems occurring with Grapelight and Win XP haven't shown in my usage, and I have found the operation to be quick and smooth, although there was a bit of head-scratching initially to work out the logic employed in Grapelight.
http://www.ludgerhesse.com/guitar-synth/GR-33_Patches/gr-33_patches.html