I do have to agree with Diety's points on Link's lagging. Such as yesterday I was playing as Zelda (just Zelda, no Sheik involved) against a Lv9 CPU Link on Final Destination (no items). And everytime Link would attempt to grab me with the Clawshot, I noticed a lag so I step out of range walk up and grab him instead. So despite him having a ranged grab attack, if you can predict it, then it leaves Link open to attacks.
His Swordspin seems pretty fair when it comes to recovery or an aerial move, it doesn't cause any real knockback in unless your hit with the final strike, however the on the ground is a different story, especially when your opponent is spamming it. And his down B (Ending Blow) leaves him vulnerable too, although Link is lucky enough to have a sheild that is pretty cheap. (Being that it can block almost anything, even a fully-charged Super Scope.)
And another note: In a all out Brawl against 3 CPU's, Link is a dirty little KO stealer. Same thing goes for Luigi.