Really good question :2thumbs:
Aside from looks/style and the killer sound-
1. the clutch uses springs instead of a diaphragm spring like the stock setup does.
2. it's really easy to get into, no draining oil and taking off the outer-primary business.
3. doesn't make a clunk noise when shifting like my stock setup did.
4. old stock clutch would lurch on my first shift when the bike was warming up.
5. the unit is very solid, no need to worry about your clutch basket taking a dump (problem with some models/years).
6. no primary oil to change!
7. a leak would always develop near my primary inspection cover. various gaskets and o-ring solutions were always a temporary fix.
8. no need to worry about primary oil getting into your starter and causing problems.
I know other open primaries in the past had rattling/noise issues. Karatas setup doesn't have these issues.
Honestly I don't know why more people don't get them :up: