As the current owner of the ex-gfen Streamflex 10' 3wt, I'll attempt to clarify.
The Streamflex is probably best described as a "specialty" rod. It excels at nymphing - especially with little or no fly line out of the tip. It's length helps keep line off the water, and it's soft tip helps cast leader only rigs. It also cushions tippet when fighting fish, and helps when fighting small fish - not to say it won't handle larger fish.
All that said, it will do other things like casting dries, swinging wets, throwing light indicator rigs, and even throwing small to medium size streamers. Is it the best choice for those other things? No, but in a pinch, it'll do an adequate job.
My advise would be to choose a rod that excels at what you intend to use it most for. If you want a small to medium size stream nymphing rod, the Streamflex is a great choice. If you want a rod that is more versatile, a 9' 4wt might be a better choice. YMMV...
