Either a 1.5 or 2 way clutch type cause additional tire wear. The wear could be trimmed or lessened by adjusting the initial torque setting. You will most likely get clunking from any clutch type out there. I have personal experience with Kaaz set to 80% lock and it wasn't pleasant to drive at all on the street. Although, another user on Nissanforums.com said he noticed very little or no clunking when he set his lock to ~60%. Currently, I'm using an OS Giken unit and it is very, very smooth and drivable. I do get an occasional clunk here and there, but it's almost rare that it happens.
Another thing I noticed using the Kaaz 1.5 with treated plates vs. the OS Giken is how quickly the unit locked. Kaaz makes its presence known with a harsh and quick "clunk" whereas the OS Giken is very smooth and seamless. Keep in mind the OS Giken is maybe $300-400 more than a standard Kaaz unit. Also, All clutch type units will require oil to be changed after hard driving, etc. Another issue is clutch plates will eventually wear out. Both companies do offer a rebuild option, and I'm sure others do as well. So keep that in mind. Though, speaking with professional drivers and various shops, the OS Giken LSDs work perfect after 3+ years of abuse.
Also you might want to read
THIS LINK to get a better idea of the different types of LSDs out there and their respective reviews.