Just constantinian christianity dressed up in sheeps clothing. Been there, done that. Don't bother.
Does JFJ believe in the divinity of Yeshua, don't they? Just wondering.
Most Jews who join Jews for Jesus are nominal Jews in the first place. There are many who return to Judaism once they really begin to study. There are testimonials on the http://www.messiahtruth.com website (check out the guest book) and elsewhere. I recently came across this one, "Escape From Counterfeit Judaism" on another site:
http://www.angelfire.com/theforce/oneishashem/