Ilac Centre is very good (weekend staff, especially), and Stephen's Green is a frequent stop for me also, but the Argos in Jervis Shopping Centre is the place to be. Great team of people employed there who always, ALWAYS go out of their way to help out, be it with advice or stock inquiries.
And they're very good when it comes to honouring reservation prices, too, unlike another Argos store I visited a while back who made a big to-do about this (whose name I won't mention, because I wouldn't like to put it out there that the Dundrum store did this).
The point is this: when you're in the city, and you need to buy something: buy it from Argos. and if you're buying from Argos, the best service is in Jervis. read more