The best one out of these 3 is Blaziken, hands down.
Blaziken
Being in the Ubers tier, it is clearly the best of the three as it gets access to one of the best abilities out there, Speed Boost.
Not to mention it's other great moves such as Swords Dance, Flare Blitz and High Jump Kick.
Moveset:
Blaziken @ Leftovers
Ability: Speed Boost
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Baton Pass
- Protect
- Substitute
- Flare Blitz
Infernape
Coming in 2nd place this fiery monkey is currently in the UU tier thanks to it's ability Iron Fist and access to moves that get a boost from said ability.
Moveset:
Infernape @ Life Orb
Ability: Blaze
EVs: 252 Atk / 252 Spe / 4 HP
Jolly Nature
- Flare Blitz
- Close Combat
- Thunder Punch
- Mach Punch
Emboar
This one is the worst of three (but still the bulkiest), It's in RU since it's amazing hidden ability Reckless is currently unreleased, meaning it cant be aquired legally.
Oh, and it can learn Scald.
Moveset:
Emboar @ Life Orb
Ability: Blaze
EVs: 72 Atk / 252 SpA / 184 Spe
Rash Nature
- Fire Blast
- Grass Knot
- Superpower
- Sucker Punch