I grew up around Christianity in the American south and this is very true. The genius of Christianity is that it's a mind virus: In order to be a good Christian you have to convert others to Christianity. It's the GPL of religions.
One theological difference – the Catholic Church teaches that it is possible for non-Catholics, non-Christians, even atheists, to go to heaven. (See Vatican II, Lumen gentium, paragraph 16 [1].) This is different from many Protestants who believe that everyone who dies non-Christian (infants and children sometimes excepted) is damned to hell for all eternity.
[1] http://www.vatican.va/archive/hist_councils/ii_vatican_counc...