What I like about ownertrades is the fact that you can gather all the owners at one resort and send them a mass email. I had this happen to me and it actually started discussions amoungst Waiohai owners that lasted about a week or so. Have never actually used it for a trade, however.
I did receive a good offer for a Westin Maui 2BR from a fellow through TUG.
Could not make it work last year (2007), but may give him a jingle for 2009.