I saw the movie and enjoyed it. It had its flaws but worth seeing if you're of a certain age. I remember seeing the play " I, Keano" in Dublin in around 2007. Caroline Morehan was in it and Mario Rosenstock also as Roy Keane if I recall correctly. There was a bit of a buzz around that play at the time.
I thought there would be more hype around the Saipan movie, especially running in to a possible world cup year for the Éire. Among friends and people I've spoken to, hardly anyone has seen it and it was never a topic of conversation.
I guess Saipan and the moderm civil war has been re-hashed and discused so many times over the years that there is a sense of fatigue and indifference towards it now. Roy's public persona as a Sky pundit and on The Overlap has possibly softened people's views on the whole saga as well.