What I think is more important when doing a course is looking at what software or languages they’re teaching.
DIT will be moving to a bigger campus in the coming years (although they’ve been saying that when I was there 2001-2005) but for the moment Kevin Street is where the game dev courses are.
Cost of living around there if you move into town isn’t bad, as long as you stay away from the expensive convenience stores, courses in DIT are generally more practical & hands on, and many of the courses have organised placements. It also runs stateofplay.ie and has Hugh and Bryan there who are top notch.
There are a couple of cons, if you’re into sports, DIT hasn’t got a big campus like UCD does or many sports facilities (although Kevin St does have a pool), and you’d probably be moving between kevin street and aungier street (200m). You do have Camden Street and all of town at your doorstep for going out, and I had a great time there, both in the social and academic side.
As for whether it’s the "prestige" of UCD being better known internationally, the games industry is a meritocracy, just pick the course that most closely matches what you’re good at, or want to learn, and choose that over a name. At the end of the day, completion of any course shows an employer that you’re capable of learning to a certain standard with expectations of improving from there, and you’ll be trained up in a particular direction once you get your foot on the ladder. The degree is rarely the be-all and end all. Showing that you’ve been working on projects through college and getting a 2.2 at the end is as likely to get you a job on the other end than having a 1st class honour, but no real-world experience.
Hope this helps!