Not sure how true this is but I just read about it and it seems that
bushings are better for high impact, low speed joints.
Not sure if that answers your question (hey, I'm not doing Mech. Eng., I'm in Comp. Sci.). I don't know what that means but that's what I found after 30 seconds on google.
EDIT: lemegacool: It seems that bearings applied properly provide better alignment, less friction, and last longer. (This is from a motorcycle forum so I don't know how relevant it is to this)