I've used the Sima SCC, too- I still have it. It was/is GREAT to remove macrovision (or whatever other names anti-copy functions go under). Also have used it to provide true "greyscale" for black and white material with excellent results. I NEVER used it to jerk around with actual color correction...WAY too harsh, made most everything I tested look worse- I personally wouldn't recommend it for an application such as that.
I had to save up/wait/shop around until I could realistically afford a proc amp. I got the Elite Video BVP-4 Plus unit that the admin references. And;
When I first tried it, I admit that I wished I had acquired one sooner. The Sima unit does work, but the Elite device makes the SCC model seem as though it were built and marketed by Fisher Price...