Actually Steve, in their day Streamline and Simms were pretty much neck and neck in the race for supremacy in the Neoprene wader market, I was a dealer of both - as well as Orvis.

Streamline disappeared from the fishing scene for reasons that weren't really product related.
If you could go back say fifteen years or so and look at the mail order catalogs of some the largest fly shops, you'd find that Streamline was a very prominent player.

All the best, Dave