Well, Paul, as you know, the S-glass (12 million modulus) rods are amazingly light compared to the standard E-glass. My go-to Sierra stream rod is a Winston 3-weight (rolled by Fisher) made with S-glass circa 1985. It is a truly awesome fishing tool.
While there are a few mainline manufacturers still making fiberglass rods and blanks (Lamiglas comes to mind), the really excellent blanks and rods are being made by Mark Steffen (
Steffen Brothers Fly Rods) and Mike McFarland
McFarland Rod Company.
Of course, all that is not to say that other old rods are not fishable. I have a nice 7' 7wt Silaflex rod (pre-Browning) that is a lot of fun to fish, even though it weighs a bit more than a modern blank. And the Fenwick Feralites are excellent rods too.
I prefer the pace of fishing with these rods. You just can't rush your cast or you get into trouble. This, in turn, provides a much more relaxed day on the water, with a completely different appreciation of even the smallest trout. There is nothing quite like sneaking on hands and knees up to a slow-moving section of water, gently laying a cast on the pool in a way that does not send the fish skittering for cover, and tempting a trout to slowly rise up to take your offering. This is the angler's art in it's truest form, and very hard to accomplish with a telephone pole.
Buzz