The Fergie Jenkins league is brand new, it joined two league's together one of which was the ECPL I thought. I know someone whose son is playing in the one age group in this league. He seems to be happy with how it's going so far.
The PBLO I think is still the premier league in Ontario. This is based solely off of my own personal observations of the amount of kids going onto to American Colleges and getting selected in the amateur draft.
Also to be honest I don't really see a need to be playing in those leagues at the 13U level and lower. A lot can happen around the ages of 12-14 both physically and mentally for kids in regards to Baseball, and that's a pretty good chunk of change to be "investing" in a kids development that really at that point in time is a cr*p shoot.
Again just my own thinking and observations.