As a "native" person from Portarlington, I can comment on how the town has grown over the past 10 years. The town is pretty much a sleepy town and is fundamentaly a commuter town for people working in Dublin. The town itself practically empties during the day. There is no "industry" in the town. They are trying to change it and the Portarlington Enterprise Center has recently opened, where they are trying to encourage enterprise in the town.
Anyway, I am one of those people that evacuate the town to Dublin on a daily basis! I was a train traveller for over 9 years between my college days and then 5 years for work! It just wasn't dependable! Particularly in the morning when the "steam train" would pick you up more often than not, only to break down again on the way... The evenings were no better! Heat on in the Summer, none in the winter...
So I have been driving to Tallaght for the last two years and it has been great! An hour door to door and the work on the N7 which looks horrendous doesn't actually delay you too much! Traffic management has been excellent... I just cant wait until they have it finished! It should shave off another 15mins each way!
Life in Portarlington is fine! Lots of pubs, restaurants and adequate shopping... There is alot of building going on, but the house prices really do hold great value! We bought 5 years ago and our house value has increased by about 65% in that time! All relative I know, but a nice increase!
Finally, if you were asking me if it's a nice place to live! I would have to say yes! Particularly these days for people working in Dublin and wanting to get out of the hectic city