If you're talking about Birijion, they are completely different Pokemon. Birijion is great because it holds that really awesome anti-metagaming niche. Salamence, on the other hand, has about half a dozen dragons competing with it. Birijion's bulk is similar to Latias' (Less physical defense and basically the same special). It's really about what they do in the metagame. It's like comparing Vaporeon to Tentacruel in gen 4. I mean, Vaporeon was CLEARLY better, right? Then why was Tentacruel OU?