We had Dd on the list for Andrews - I played hockey with a club who used their grounds for a few years, the students always seemed really polite and in there lots for sports and supervised study in the afternoons/weekends (not common to many schools here). They have things like Model EU and Model UN, and are big on debating etc. And a good reputation for academics. So overall seemed a good fit for DD. Protestant ethos, which I believe is not hugely "down your throat" but a good all round moral grounding. And generally aim to look at the whole student, not just getting strong academic results (but among the top schools for students going to 3rd level).
(She's got into a school closer to home that suits slightly better with equally good reputation, hence no longer considering Andrews. We also had a Quaker boarding school on our list - slightly eclectic in seeking non-traditional RC but having a good moral code.)
See a lot of Andrew's students on the train (DART) or the bus, along with students from Coláiste Eoin and Coláiste Iosagáin (the boys and girls Irish secondaries - VERY hard to get into and all done through Irish). The 2 Irish ones are on the same campus, and Andrews is up the hill to the next junction and down the side road - about a mile or so apart. You do see a reasonable amount of interaction between the various groups of students, and in a nice way (not like some of the rivalries between certain schools).
I've also played hockey on Alex's grounds - what I know is good about them. Mix of boarding and day, only girls, protestant ethos again, any students I've met have always been very polite, strong hockey teams. I think they are also strong on developing the whole student, not just the focus on academics - from what a few friends have said. But Alex is a bit out of our catchment to have really paid attention.
(And while we are in an Educate Together, DD did swimming lessons, and lots of summer sports camps, in Castlepark - lovely grounds, great sports facilities, swimming pool (unusual in Ireland for a school), and I think they have afterschool club until 6pm daily. And hot lunches - which DD actually ate at camp (she can be fussy, ADHD and aspergers so not entirely "just fussy"). And all the staff in sports centre handled her very well (brought her out of her shell, and were able to manage any meltdowns etc that did happen there - rare but there were a few over the years).