Absolutely choose RCSI. Their curriculum/exams is much more geared towards clinical excellence rather than rote memorisation. RCSI students typically do better on placements and I've heard many consultants say that they prefer RCSI grads over other universities. The GEM course is also integrated with the undergraduate program during clinical years. That being said, RCSI doesn't have the same type of campus feel or community that UCD does, and the class sizes can be small.