Compound rubber or polyurethane bushings are the most widely used, cost-effective, and easy to come by. Since they are inexpensive and generally easy to replace, they tend to be a great joint for the entry- to midlevel wheeler. Since they are the least rigid, they tend to allow the joint and attached suspension link to rotate freely while helping to absorb vibrations transmitted from the wheel.  EZ Wheeler offers brands like Daystar, JKS and Zone offroad.  With companies like this you can be sure that you are getting a high quality bushing that will last a long time.