"I don't think the 100% thing is a lie, as I personally have not ever heard of anyone who failed to obtain residency of those who applied. Some pre-matched."
Exactly -- "of those who applied." While the success stories are touted (Harvard, Hopkins, Mayo) there are many if not more who don't match because they can't get through the boards and, therefore, "don't apply."
While it's possible to get a very competitive residency as an FMG from Ireland - before you head off, I encourage applicants to take a hard look at themselves and ask if they have what it take to takes to prove to US residency directors that they didn't "need" to go abroad (IE: smoke the boards).
PS: so that you don't think that I'm just bitter - I happen to be a PGY-2 at one of the above three institutions.
Mick