Pure-Types vs. Dual-Types

[Zenax]

I'll go with the flow and say dual-types. However, it depends on the Pokémon as a whole if two types are better or not. For most defensive Pokémon, having a Poison or Steel subtypes helps because of the various resistance they bring, but an offensive Pokémon might prefer something like Fighting or Ground. Some Pokémon are good even without having a subtype (think of Mewtwo, Kyogre or Darkrai. They're legendaries, but still).

 

[Miar]

Dual-types cover more bases in offense and sometimes defense, so those.

 

[TerraTF]

Dual Types have a better range of STAB

 

[Water Max]

I prefer dual types because there are two types which the pokémon can use STAB for and it allows you to easily have at least one move of every type in a party. I think the disadvantage of dual types is it normally makes the pokémon have more super effective or neutral move types against it.

 

[RiverAura]

I'm choosing dual-types, but simply because I like seeing how they designed Pokémon to create the more original combos. Other than that, though, I don't really have any preference. Some dual-types should have been pure, like almost every normal-flying type in existence. Likewise, some pure types probably could have used a second type (looking at you, Samurott and Serperior). Honestly, whether a Pokémon is pure type or dual type does not inherently change their usefulness. It's all about how the types work together with other types, and against other types.