The biggest problem with PSLF is the "PS" part. In my city, two of the three major medical centers are for-profit, and while some of the fellows I have worked with are still in academic medicine, many of them have moved on to for-profit practices. The aspiring medical student needs to know about all the programs (not just the federal PSLF program which applies to all public service jobs, but also state and local programs specific to physicians) and match the program to their career plans.
But, it is definitely a concept that should be explored before draining the parents's retirement funds!
