Machamp vs Heracross

Both have the same base attack (234). Heracross have 27 more defense and Machamp have 20 more stamina.

I simulated a battle in Pokeassistant considering both level 30 and 100% ivs, no dodge and both C/CC.

Heracross wins.

But if you consider a C/DP Machamp, Heracross lose.

Heracross has lower HP, but higher DEF, so their effective HP is pretty similar. But heracross has double weakness to flying type by virtue of its bug typing, so I'd say Machamp comes out slightly ahead against the best gym opponents.

In this case (counter/close combat) Heracross is the most potion efficient. (They do the same damage) But Machamp counter/dynamic punch is the best fight attacker.

If you live in south america, south florida or Mexico and machop is rare (like me), heracross is a good choice. DP is better then close combat, but CC does the job just fine.

Against what?

I just tried them out in my gym simulator and found the following.

If you assume perfect dodging of Blissey's charge move, then they are exactly equal.

Both:
Lv. 30 Machamp 15/15/15 - Counter/Close Combat
and
Lv. 30 Heracross 15/15/15 - Counter/Close Combat

Defeat
Lv 30 Blissey 15/15/15 - Pound/Hyper Beam

With 48.5 seconds remaining (in the 64th round).

The Heracross has 16 (out of 128) HP remaining while the Machamp would have 19 (out of 143) HP remaining.

I also tried it assuming you only manage to dodge 80% of the Hyper Beams, even then they end up with exactly the same two outcomes (either win because they dodged successfully or lost when they didn't).

Overall they're closely matched, so the differences will come down to type matchups. Feel free to try the simulator out for yourself and see where they work for you.

https://docs.google.com/spreadsheets/d/1TGMj8MK90hMYmvehzCLyEu4roXswLJlIC4h7-pmyj5I/edit?usp=sharing