I'm an intern at MCH- I started only a few months ago but I'm happy with the program. There are 2 programs in Miami - MCH (miami children's hosp) and Jackson (university of miami). Both programs are very good but very different. MCH is a private hospital with excellent subspecitalty services (including some of the country's best surgeons and neurologists) MCH is a stand-alone children's hospital ranked top 25 in the USA in US News and World Report.
Jackson in a huge city hospital affiliated wi the Univ of Miami. The program is known to be more "hands on" and "resident run" - meaning residents draw blood and even transport patients. It is in a more urban setting and care involves more "urban issues" like HIV and Hepatitis.
You should attempt to interview at both programs and see things for yourself.
I hope this helps.