Thats a really nice idea and the price sounds pretty good, compared to some I've heard! Have you seen them perform?If you could get them to do a bit of ceili dancing its usually good craic too, gets some of the guests involved! I did irish dancing for years and hoping to do a small display with some of my BM, if I can get fit enough again!lol
If it's what you really want go for it. But I'd want to hear them play before booking.
One thing though, I went to a wedding last summer and they had a ballad group playing. I enjoy a ballad sesh myself, and the band were fab but its not everybodys cup of tea. Nobody was out dancing apart from a handful of people and the dancefloor remained empty most of the night. Speaking to people outside in the smoking area they weren't going down well at all. And by the time the disco started at midnight the atmosphere was lost and a lot went home.
Would have went down a bomb the next day though! Maybe for the day after?? And just have irish dancers with backing music at the wedding?