You are amazingly lucky - there's 14 rooms in this place and by pure chance I'm in one of them. The rooms are NOT big enough for you to bring all your stuff, that I can assure you. I do not have anywhere near enough space for only me, and the double rooms are not much bigger and do not have loads more storage. You will have one wardrobe, a chest of drawers, a small table with a couple of chairs and a desk. The kitchens are nice but not big if everyone wants to cook at once (unless you are on the top floor there are 5 rooms to a kitchen, and if some of them are couples rooms thats a lot of people) and there are again space issues in terms of food storage. It is exactly the same as living in ordinary halls except quieter and the rooms are a bit bigger.
It is right next to St Pat's - I pretended to be a fresher and joined in all their halls stuff and no one minded or noticed, I met a lot of my friends that way. NCH is very quiet, but people are friendly enough, most of the people that live here are American and most others are European. I wouldnt expect any sort of social life to come from this house, so you will probably want to look to people on your course/societies in terms of a social life.
Just to clarify what Grotbag said above: non-students are allowed to live here, we have several non-student partners floating about here, and it isn't part of dedicated family accommodation. Most of the people here are single postgrads and the occasional couple (one per floor I think, maybe 2) - there are no children.