Dr. Losito is first and foremost a great guy. People love him and there is good reason. At least that is my opinion from my brief encounters with him. I don't think you will hear much different from anyone else.
But to clarify, if by accredited you mean by the CPME then yes, it is. But there are ACFAS approved fellowships in sports med in Seattle and Palo Alto. We can talk about why CPME accreditation may actually be a bad thing but that is beside the point. I think it would help to land Losito's fellowship if you went to Barry (a lot of opportunity to interact/work with him), but don't think it is the ONLY chance you have to get extra training in sports med.