I had a 4wt Sage 99. It was actually one of the first production models made, if not THE first one. I won it on flyanglersonline, and it was sent out directly from Sage, months before they appeared in fly shops.
It threw dries exceptionally well, and had no trouble with some pretty hefty streamers.
The action was a bit odd. It had a really stiff tip, and a softer mid section. This series was designed for heavy indicator rigs, and wasn't the best tool for fishing Euro style. The stiff tip resulted in a lot of "bounced" fish - especially the smaller ones. The tip was just too powerful to provide a lot of shock absorption.
It really excelled at throwing heavy indicator rigs, and the soft(ish) mid section made throwing more open loops easy.
All that said, I really liked fishing it. It was great for switching up between different fishing methods if you only carried one rod.
The stiff tip and softer mid section that hindered landing small fish did far better at landing big fish. With heavier tippet, you could really put the lumber to 'em.
This is one of those rods you either love, or hate. I liked it but it wasn't the best tool for the type of fishing I was looking to do with it (Euro-nymphing). If you're looking to throw heavy indicator rigs, this may be the best rod ever for that - it was designed for it.
YMMV...