If you live in Ireland, people are more likely to pronounce Irish first names more or less properly (even if they don't know Irish, they have heard of people called Ciarán etc). In other English-speaking countries I don't know, I guess most people wouldn't pronounce them properly, as Redwolf said.
When I have children, I wouldn't choose an Irish name (at least not the "official" first name) because I won't want their name to be badly pronounce all their life except by me or when we go to Ireland

I'd rather choose a French name that has an Irish and a Breton version

(hope they won't be perturbed being called by 3 different names

Anyway, in my opinion children don't like when their first name isn't pronounced properly (especially when that happens 100 times a day) and might hate you for giving them a too strange name

I know some people in that case...