CSW is just as good as BJJ. It is a no-gi system of Paulson's personal combination of judo, muay thai, boxing, BJJ, and wrestling. That makes sense because that's part of what he added when he studied JDK. I regularly trained at a CSW place for about 2 years, and I still incorporate it into my style where possible. I like the lockflows in CSW and the "grappling with strikes" that is used instead of simple "grappling" rolling at times.
Both would do you well. By itself, CSW may be a little better for MMA for some people too, IMO. It really does feel like no-gi at a BJJ place. Erik refers to the groundwork as "jiu-jitsu" or "wrestling." I was at one of his seminars today. The man certainly knows his stuff and how to teach it well. Go to an Erik Paulson seminar if you can find one (after training either BJJ or CSW for at least 5-6 months - otherwise you won't get much out of it except confusion). I find BJJ instructors are usually a little more technically minded when instructing, but not by much. I think my CSW greatly helped my BJJ.
I believe most "CSW" fighters either call themselves wrestlers, grapplers, freestyle fighters, or just MMA fighters. That's why you don't find too many guys claiming CSW as their style even if they train it a lot.
