I lived there for a couple of years until 2 years ago. I thought it was a really nice spot. No real noise or social problems at all. Very handy for Dart and decent enough bus service.
Monkstown is a nice village, few decent restaurants, wasn't a huge fan of Goggins or The Pub but alright. Very handy for shopping in Blackrock or Dun Laoghaire.
I was in a 1 bed apartment on the top (third) floor, it was fairly small with poor storage, that's the only negative I can think of, oh and sometimes there was some really dodgy parking on the entrance to the estate as it's one of the few free places to park in the area so you have DART/Bus commuters dumping their car there.