1) From my understanding, and after speaking to my Irish classmates, most of the 4 year programs are pretty similar to each other. The calendar year at UCC is longer than the others, as we started mid August while the other 4 year programs didn't begin until September. Another thing I learned is that clinical rotations begin very early at UCC, as in January of the second year. You will do a few rotations at that point, as the current second years recently finished two months worth of rotations it seems and are now back into lectures. The early clinical exposure is likely due to the extended calendar year.
RCSI is clearly known back home in Canada, but the education doesn't seem to be better than the other programs and in my perspective, doesn't justify the increased cost. Trinity isn't a 4 year program but is the most well known back home. Every time I mentioned to physicians that I was going to study medicine in Ireland I was asked if I was going to Trinity. I've heard that the medical school there gets a reputation from the university itself and that it doesn't mean that the medical school is necessarily a fantastic school.
2) I have a friend attending at Limerick, and I have some people on Facebook who I attended the Limerick interview with. From what I've been hearing, it seems as if people may be regretting their choice of going to that school. They seem to be incredibly stressed out and my friend keeps telling me he wishes he had more lectures as opposed to his problem-based learning. Also Limerick has no cadaver lab, and no amount of telling me that their computer models are fantastic and it's a good equivalent will change my mind that this is a huge drawback. That lack of hands on experience is a big problem for me. So therefore, in my mind Limerick is a less desirable school. I was rejected from there and so it may seem that I'm on an angry rant about the school, but after hearing these things it makes me glad I wasn't accepted.
3) Only RCSI and UL require interviews. I received my acceptance to UCC near the end of April. Stats weren't anything to brag about, 3.0 GPA, 27R MCAT.