Tails is ranked 2nd in the tier list. He has one of the best recoveries in the game, as his extra jumps allow him a lot more range and flexibility in his methods for returning to the stage. His Electron Cannon allows him to fire energy balls that have infinite range and can be fired in three different directions (forwards, upwards, and downwards in the air), giving him strong stage control, versatile zoning abilities, and a strong edgeguard. He has some of the best instant kill attacks in the game, including aforementioned up/down energy balls, the only projectiles with instant kill properties in the game, as well as Tail Attack, one of the few instant kill attacks that is not mapped to an up/down move.
However, he is not the strongest or most durable character in the game. He lacks the ability to cancel his momentum in the air, making him vulnerable to getting KOd by moves that lack instant kill properties, like Knuckles' rock. His Electron Cannon has a slow firing rate, making it difficult to challenge another projectile user directly.
Regardless, his pros greatly overlook his cons, which puts him in the top tier.
Tails fires a single energy ball forward. Deals 3% per frame, making it fairly weak at the start of the match, but at higher percents, its knockback is such that it will hit the opponent multiple times by bouncing them back into its path.
Tails fires a boxing glove on a chain around his shoulders. A reliable close-range attack that covers Tails's whole body and, while not an instant-kill attack, is good at scoring KOs normally. Deals up to 78% damage.
Tails fires an energy ball directly below himself. Deals a fairly constant 8% damage, but has instant kill properties, and Tails can act out of the animation the moment the energy ball is separated from him.