I think it depends on the players who chose Link and Kirby on Brawl, dur.
But in all seriousness, let's look it over.
Most people would see it as this: Kirby tries to suck in Link and Link pulls a "Dodongo Buster". Basically speaking, he feeds our favorite pink puffball a bomb and Kirby explodes from the inside, dying in the process. However, this isn't true. Kirby has a rather tough stomach and you can tell just by what it (I could never decide whether Kirby is a he or a she) eats. Kirby's eaten blades,
bombs, metal, rocks, blocks, and just about everything known to man. If sharp blades can't kill Kirby from inside it's gut, nothing can. Plus, inhaling a bomb from Link would probably be beneficial to Kirby because he'll probably get the "Bomberman" ability.
Also, then there's the whole thing of copying. Two ways to go about this are that A) Kirby will be put in a Dark Link scenario similar to that of AoL or OoT,
Kirby will completely copy Link's abilities, or C) Kirby will have to choose from a random ability. I'm not sure which scenario would happen, but I personally believe in C because whenever Kirby inhales two or more enemies with different abilities, Kirby has to do a sort of "Ability Roulette" if you will to choose an ability. This may very well be the same for a single enemy with many different abilities (Link).
Now then, let's compare the best of the Links, WW Link to be exact, to Normal Kirby as a control. WWL has a wide variety of items from the usual Sword and Shield to the incredibly useful weapon we know as Ice Arrows. Magic Armor and bottled items will be exempted to make things fairer for Kirby because Kirby has no artificial (as in controllable) means of restoring it's own health.
Let's say Kirby chooses not to inhale Link at all and instead decides to do things in his own unique way. Now, Kirby can fly, do an aerial spin drill attack with it's feet, and a wide variety of ground attacks. The aerial attack wouldn't be of much use to Kirby because WW Link would Parry out of the way and counter, but it's ground attacks would do very well.
Let's say Kirby uses it's hammer to stun Link. Even if Link blocked with his shield, he would be stunned and, in a real life scenario, have his shield knocked out of his hands. Then Kirby would go in and make another swing, or more effectively, begin a flurry of punch attacks to bring his Life Gauge down.
Kirby could also keep Link stunned by launching a flurry of punches until Link can no longer keep blocking and Kirby smacks him clear across the battlefield.
Should Kirby ever try to fly and begin an assault from the sky, it's pretty much screwed because Link would just fire an Ice Arrow at him and freeze him, allowing Kirby to break into little pink icy chunks. Most people would think that Kirby could easily dodge it, but Kirby isn't built for grace in the sky. It flies very slowly and has no special means to dodge airborne projectiles. Not to mention, those arrows are probably flying faster than a Major League Baseball pitch.
Another thing to take into consideration is if Link shoots an Ice Arrow while Kirby is on the ground. Kirby is much more agile and manuverable on the ground, but still there's a very good chance that the Ice Arrow will make contact. And for those of us who've played WW and know the tricks to it, we know Link would go in and attack with his hammer or fire a Fire Arrow to destroy him.
But Link's own hammer is not nearly as effective. If he tries to do that, he is open for a breif moment, a moment Kirby will surely seize to lay a smack down on Link and bring his Life Gauge down.
The Magic Armor and bottled items are exempted because that would be an instant win for Link.
The Boomerang would be Link's most effective weapon because he could use it to stun Kirby in order to make the kill.
The Deku Leaf would barely keep Kirby back at all since Kirby has run through windier places easily and with little effort. One short, relatively weak blast would do nothing and only leave Link open.
Link's Hurricane Spin would be a death sentence because Kirby could simply fly to avoid it, let Link get dizzy, and go in for the kill. Even if Link bumps into something, that still leaves just enough time for Kirby to go in for the kill.
The bombs would be rather suicidal on Link's part because Kirby would probably eat one and turn into "Bomberman" Kirby who has an unlimited supply of them and those bombs would easily get in Link's way and leave only projectiles as a solution, but that would be a quick fix because they explode eventually and Kirby can just keep throwing them and throwing them until Link dies.
Now for the ability Kirbys.
Rock Kirby would be very vulnrable to the hammer and bombs. I haven't played a Kirby game in a while so I don't remember if he can use his melee attacks in his ability forms or not, but if his doesn't Kirby's pretty much screwed. If he does, then that makes flying a tiny bit safer since he can turn into a rock and have the Ice Arrows Link is bound to fire bounce right off him.
Metal Kirby would pretty much tie it up. Link's hammer would do nothing, Link's bombs would do nothing, Link's arrows would do nothing, Link's sword would do nothing, just about everything Link has in his arsenal can't even dent Metal Kirby. However, Metal Kirby is extremely slow and cannot fly, so it'll most likely end a tie or Link is smart enough to lure it into a bottomless pit to die in.
Beam, Lazer, and UFO Kirby would have their lazers reflected is directions they don't want to go and UFO Kirby doesn't have it's manuverability or melee attacks and Beam and Lazer Kirby don't have their melee attacks. Link might get hit once or twice, but Kirby would probably get hit more. However, assuming UFO Kirby is made out of metal like real UFOs, Link would lose against the battle of UFO Kirby.
Sword Kirby would most likely die because Link has all those sword moves and a few more, not to mention he has the almighty Parry Attack, as well as a shield to defend with, unlike the unfortunate pink puffball.
Tornado Kirby would pwn Link because Tornado Kirby could turn into a twister, spin around behind Link before he can turn around and attack. Repeat a couple times and the WW Game Over Music plays.
I could go on and on and on about all of Kirby's abilities and see who wins the battle if Kirby has that ability but for the most part, Kirby pwns.
Kirby wins the battle, and a delicious Link trophy.
The thing is, in reality Kirby would absorb Links powers not his weapons and items. I know smash brothers makes it seem different but from what I've seen Kirby do in other games and shows, they were just trying to keep the game constant. Now the only power Kirby might get from absorbing Link is unlimited courage. That's the only power I can think of that Link gets without an item. Not even a sword or a bow.
Now after all that is said, I believe Link would win do to his arsenal of tricks up his sleeves.
Then explain when Kirby inhales Fox and Falco. He gets their guns. I'd hardly call a gun an ability, would you? And also, he can get needles from Shiek. Again, a weapon, not an ability. He also gets abilities such as Mario's fireballs and Zelda's Magic. Also, when he inhales armed enemies in actual Kirby games such as swordsmen, he gains their weapons. Kirby would get at least Link's sword, or more likely, an "Ability Roulette" because Link has multiple abilities for Kirby to gain.