Take a look: http://www.catholic-forum.com/members/popestleo/index.html(scroll all the way down. There is a long section on Catholic Critique of JWs)
It surprises me that they are being so vocal and so vehemently engaging in religion-bashing!
That particular site is a personal site by someone who is a former JW now Catholic.
As for the "ban" on Yahweh....it only relates to the liturgy or worship service. A priest or deacon might well use "Yahweh" in the sermon during Mass if he was speaking in the historical context of the Old Testament. The fixed prayers and the songs of the Mass will follow the New Testament practice (and Jesus' practice as well) of using "Lord" or "Father" or "God" in prayers.