I think Link wins it but it's not impossible just tedious
Link has 3 projectiles to your one, so you'll always be on the move trying to get in, Peaches combo game is a bit better in this with her tilts helping with that so it's a little easier to add damage, Edgeguarding Link is a little weird.. He can do that bomb throw thing where he hits his bomb to get an additional up b but his recovery is still pretty predictable.
I haven't played a super high level link, But I've played OK Links, and if they camp you out I do believe it is an up hill battle.
Someone can correct me if i am wrong in this.