Absolutley, Heritage no question. I've recommended this place several times on Askaboutmoney as well as to everyone I know, I unfortunately have no connection with it.
As a comparison, I've stayed in Fota Island, Faithlegg, Waterford Castle & Mount Juliet in recent years, and the Heritage stands way out on its own (although Mount Juliet - I stayed in the House - was pretty fantastic).
The Heritage Golf Course, designed by Seve Ballesteros who was also Club Captain for the first year, is a bit of a monster and a killer if you're not on form. But it is magnificent, it is the most manicured course I have ever seen. There is also a par 3 course which is beautiful, and a Sevy Golf Academy to iron out those little problems that all golfers find occurring from time to time!
And as MandaC says, the Spa ... - it's so nice I have driven the hour or so from my house to spend the afternoon there, have dinner in the Clubhouse, and driven home.