Me being a Link player, I would say that from my toughest battles, I've had, their where two characters who really gave me a tough time, Marth, and Samus. Marth's range is what really makes him have the edge over Link, I seem to have a rather difficult time trying to get in hits on him, and since Link is rather heavy, his fall is good for Marth to juggle with, and end in the Forward Smash...so yes, I have a tough time with Marth, probably for me, my worse heel when I'm using Link.
Samus isn't that hard to outgame, but it's the mere fact that Link has a rather difficult time trying to knock her out. However, Link can be easily K.O. by Samus, so that is where it poses a problem for me, where I have to literally get Samus to 140% or over to kill her, she can easily kill me lower than 140%.
Link is one of the few characters who can play well against the majority of characters, he doesn't have a big advantage nor a big disadvantage. I also agree, that before some people go on blabbing that everyone can own Link, then you probably been playing Link player's who DON'T know how to use Link properly, he is a very good character, sure he has to really sweat for his wins, but a win is a win.