It's very fast, and can KO a lot of things with outrage and edgequake. Slap a scarf on and it will out speed faster threats like starmie. Give it life orb and swords dance and it will destroy teams. Salamence can try, but he doesn't come close to the godliness that is garchomp.
Plus, he is cool looking.
It even performs well in ubers. --- "Servant woman, bring me a drying cloth at once!" - Vegeta to Bulma
Latios, Salamence, and Garchomp all laugh at Dragonite.
Neither of these posts are fair to either Dragonite or Garchomp. Dragonite serves a different role. Garchomp isn't a very good tank, but he's a fantastic physical sweeper. --- I'm not easily impressed; I'm usually oblivious to whatever's in front of me. Pokemon White 2 FC: 3139-7420-3142 - THIEF