Yeah, CMS is where I got my repro shocks. As I understood it, they had identical cases, but modern internals. The springs are progressive wound on the new ones, so they don't exactly match stock. My original OEM shocks had nothing left in them. I removed the springs and you could move the piston rod in and out of the chrome case with almost zero effort- no dampening left at all. It was a night-and-day difference in the handling.
I haven't ridden many bikes nor sampled different shocks, so I can't really speak to what's a "good" shock versus a "crappy" one. (Except when the shock is worn out!)