I really liked Streamline a lot. I was in the silk screen industry and it was a godsend. If you have a good B/W source, scan it in at high-res, I am talking 1200dpi. Adjust your settings, and I always got very good results.
Depending on what you were doing, there was little edting. Color images on the other hand were something else altogether, which I rarely used but it often gave me a good startin point for spot color seps.
Adobe seemed to have swept this little app under the rug and forgetten about it. There is no OS X version available and none announced. I think they could easily integrate it into Illustrator, as they did with Dimensions, and get rid of the junk tracer thats there now.
What made Streamline valuble was that it did do what it offered, for only $130 bucks. Other vector tracers were very pricey.