I saw on ebay a guy selling a CV conversion for the U Joint prop shaft. He claimed that it was less maintenance, but are they any more or less efficient? U Joints are easy to change, and easy to grease. I don't know much about CVs. Is this anything worth upgrading?

FYI, I have a 96 Sportsman 500.

 

IMO; CV joints are better balanced, better able to handle higher angles, and are sealed from dirt, mud and water.

IMO CV joints are much better than the old U-joints, thats why most on and off road veichles are coming with CV joints.