Since I've been seriously contemplating the priesthood for about a year and a half now, this question arose, because I want to leave the US for somewhere in Europe.
If there is a high need of priests in the US, I'll stay here. But if they're more needed in the UK or Ireland, I could be a priest there, and get to live in Europe too.
Really, it's just a matter of where the need is though. So, where are priests needed the most: the US, UK, or Ireland?
(PS if they're really really needed in some non-English speaking European nation, I might consider that too!)