Actually, we discussed that S-90 here as well. It was mine. That's what I traded to Karl for the very cool Garnet Lil Rock amp head.
The S-90 was my first Guild. Followed shortly thereafter by two others, a '74 S-100 (w/o the stock p/us), then a '75 SF VI. In a sense, the S-90 became expendable once I got the S-100, as I prefer that guitar layout with a bound neck, and the S-100 is an easier player.
However, what made this a hard decision was the pickups in the S-90. Truly outstanding. Some of the best sounding p/us I've ever heard. I thought hard about keeping the p/us, swapping them into the S-100. But just couldn't do that. Bad enough someone did it to my S100.
So that's the deal. The S-90 is one cool instrument. BTW, Guitar Barn is always worth the trip. I've bought and sold many things there through the years. Karl is an easy guy to talk to. I drop by there as much to say hello as to cruise the guitars.
MD