Go for the FG-335, no question.
You don't mention the prices, of course that counts for a lot.
Go for the FG-335. The FG-335 is a great guitar with consistent quality across specimens. If it's in decent shape you're almost guaranteed to get a great guitar. An FG-335 will probably cost you only $150, perhaps less. FG-335s sound great, tune well, are easy to play, are durable, and are fun to throw around everywhere you go. You almost can't lose. The FG-335 is a big success story in the history of guitars and changed the playing field back in the late 70s. Everyone should have one.
The FG-375S, while possibly a fine guitar, is not a famous success story like that. Who's ever even heard of it? An FG-375S is worth $300 or more and you won't want to toss that carelessly into your back seat. If you really need those gold tuning keys, just spring for a set on ebay and install them onto the FG-335.
In my case, I played an FG-335 in the music store back in 1981. Even I could see that it was a fine guitar, easy to play and sounding good. Having more money at the time than wisdom, I told the salesman to sell me the fanciest version of that guitar. He ordered me the FG-375S and when it arrived I found it not to be the same at all. Pretty to look at, but difficult to play and didn't sound great like the 335. I was sorely disappointed and never liked it. It got stolen after a few years and I was glad. I replaced it with a garage sale Alvarez classical for $15 and that was a better guitar that I've played for 20+ years now.
No question, unless you are stealing the 375, or even if you are, go with the 335 and you'll probably never find a better guitar.
(to those people that think we shouldn't post to old threads, let it occur to you that there's a recent invention called "Google" that keeps threads relevant forever.)
