I've also been looking at those programs (I'm a peds PGY 3), and met one of the Hopkins PICU attendings the other day. From what she and others have said, the fellows/residents are excellently trained, though the 5 year fellowship is tough. You come out certified to managed OR patients and PICU patients, and you come out being good at both. My understanding is that eventually you'll end up choosing one or the other, however, especially since a lot of PICU docs tend to burn out. I'd be very interested what others here have to say though.