Organizationally i believe there are many similarities between the Watchtower and the Roman Catholic Church. Some have been listed above.  I try to distinguish between the people and the Organisation/Church.
Last week i went to the funeral of a lovely sweet kindhearted Irish Catholic Lady.  Molly was one of lifes living saints.  As a young girl she left Ireland and came to England.  She fell in love with a young man and became engaged.  Sadly her Fiancee died and Molly never married.    She spent her life showing love and compassion for everyone she met.  She would visit the sick, work on soup kitchens, in fact its hard to say what charitable work she did not do.  Me and my wife enjoyed many a meal at her home and she at ours. Even up until she died she would visit my Mother-in law in her care Home.  I could go on and on.
At her Funeral you could not get inro the Church such was the mass of people who wanted to show thier respects.  Her funeral was a testimony to her life.
In my opinion most catholics do not really know what the Church teaches, let alone agree with those teachings.  Shane sums up the Irish situation very well.   Religion throws up saints and Sinners.  The Catholic Church has produced its share of both. The Catholic Church has now lost its iron grip on the people, the Watchtower retains its power.
I have more to add but have to take my wife to work...in the local Catholic School.