Philobiblon provides a discussion of part of the impact of the pre-Christian Roman invasion of Celtic Britain in What the Romans did TO us (i.e. women). Say what you will about the Roman Catholic Church's attitude toward women, they saved female babies from being treated as disposable. Besides, nobody's yet proven that any Christians performed mass slaughters of Druids (hint: when you see an Irish saint's life story, treat it as propaganda, not historical fact). The Isle of Mona massacre was not run by a bunch of priests.
And in yet another moment of modern innovation for me, I refuse to let history tell me how to react to Nova Romans. I prefer a more balanced perspective on modern times.