Studying at DCU was definitely the best experience I've ever had in my life. Getting to know some of the nicest and most helpful people I've ever met, speaking English all the time and having the opportunity to take modules I can't take here in Brazil make me don't have anything to complain about the Exchange.
DCU staff were always there to support us and they were always trying to make us feel the most comfortable possible. DCU has a big campus, with lots of facilities as restaurants, a drugstore, a bank and some ATMS around, besides the huge library where you can find some really important books.
As an Engineering student, I could learn a lot from the modules I had taken there - from bionedical engineering to programming and image processing modules.
DCU accommodations are very good, maybe the best I've seen in Dublin, and they are all inside the campus or quite near it.
Visit NuBar, go to the Albert College Park, join a society or a club... enjoy DCU to the fullest. I can tell you: YOU WON'T REGRET IT ;)