Im double posting but this is relevant so I will.
Heracross. The boosting sets are too slow and are generally done better by Lucario, Scizor, and Infernape. Scarf Heracross is good, although it gets walled easily due to the lack of power to break through common pivots and lacks resistance to priority. Although when it comes to hit and run pokemon Heracross has his niche. Boasting greater strength than Choice Band Tyranitar with both STAB moves, he can make very many teams cry and get crushed by his heraculean strength. These are the sets I'd argue which makes Heracross better than what he is ranked right now.
Heracross (M) @ Choice Band
Trait: Guts
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Stone Edge
- Megahorn
- Close Combat
- Pursuit
Heracross (M) @ Life Orb
Trait: Guts
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Sleep Talk
- Close Combat
- Megahorn
- Rest
Heracross has a useful defensive typing, resisting fighting, ground, bug, grass, and dark. I personally believe Heracross functions a lot better in the modern DPP OU metagame instead of the steel dragon one where Salamence was legal. People can argue that Infernape is faster and has U-Turn, but Heracross has very great power and decent bulk. Heracross is also less prediction reliant because of his checks and counters.
Zapdos, Gliscor, Gyarados, Dragonite, Rotom-A, Tentacruel, and Gengar, Skarmory. All of his checks and counter get 2hko'd by his STAB moves (or take around 40% making them shaky switch ins with possible SR and Sand), making the only prediction you need a 50-50. Lets be honest, Choice Band or Guts Boosted Rest/Talk Heracross 2hkoing a 252 HP Dragonite with CB CC after SR is extremely satisfying 42.4 - 50%. The listed damage calculation is CB Heracross vs 252 HP Dragonite, but it is safe to assume a sleeping guts LO Heracross does even more damage. He can get stronger from Toxic Spikes and WoW.
He doesn't have U-Turn like Scizor or his typing, but Heracross is faster, can check Breloom, and break walls more easily. The popularity of Bold Starmie in DPP OU helps Heracross's case. Bold Starmie checks fighters like Lucario and Infernape very well. Heracross doesn't really care that much since he has Megahorn. Infernape plays best as a physical mix sweeper. For him to hit Bold Starmie hard as possible, he needs to go out of his comfort zone and run Grass Knot. That is also a risk because Infernape can never tell if the Starmie is slow or fast unless with damage calcs or with Sand. Infernape is also a little more prediction reliant. Lucario is easier to shut down early on since Lucario is generally a late game mon, and has more moveslot syndrome than Heracross does. To be fair though, Lucario can spam powerful CC's to scout or revenge stuff with Extreme Speed.
Rest/Talk Guts is also a very big niche for Heracross. A Rest/Talk offensive pokemon which gets stronger and can use Life Orb. Working well with the popular Starmie and wallbreakers. I like the sound of that. Weavile is also a good partner for the Rest/Talk set to get rid of ghosts and to check dragons. I don't use Tyranitar because sand is bad for Heracross. Mix Flygon is a good partner for his typing and his ability to break the cores that Hera has trouble with.
Heracross is very underrated, is a forgotten threat, and is a great pokemon in the current DPP OU metagame. Very anti metagame. (As long as you don't fight Crobat!)
PS:BKC can vouch to the usefulness of Rest/Talk Hera. I also have no idea why Magnezone isn't in B. The Protect Leftovers sets with Toxic or Thunder Wave are good. Choice Specs Magnezone is also pretty good.