Hi Daithi, I stayed in the Athenaeum last year. It's a class spot, would definitely recommend it. We were a bit flush at the time so got one of the suites, which are huge and very nicely decorated, with open fire, jacuzzi and everything. The restaurant is of a very high standard as well.
It's not a huge hotel so I felt it had a real personal touch to it - we were chatting with the owner Stan Power who seemed like a nice guy and as far as I could see was making an effort to talk to most of the people staying there. Highly recommended - we're saving up for a return visit!