Sorry for the delay... just spend 2 weeks in Alaska
and am getting caught up on the 700+ unread e-mail messages between home & work!
Anyway, I had an RG6CST for a while and really liked it. The combination of the thicker neck (probably an Ultra) with the ebony fretboard was amazing--definitely one of the smoothest Ibanezes I've ever played. I think the lack of inlays is very sharp looking. The tone was also great... the combination of the PAF Pro and Tone Zone in mahogany has always been one of my personal favorites. I think it sounds slightly darker than a 3120, but not by much, which is probably just the tonal difference between the swamp ash & maple.
The finish is more of a matte finish, so it tends to ding/scratch a little easier than a thicker clearcoat finish.
The grain on the top tends to vary a lot, so make sure you see pics before you buy. Not that I've ever seen a "bad" RG6CST, but you never know.
This was one of the J-Custom models that was imported to the US to show off the double-edge trem back in 1999. I don't know whether 12 or 24 were made, but either way, it's pretty uncommon.
Anyway, it's a killer guitar!