Since Brute force is the best way to go in-game, Rhyperior is clearly better. Rhyperior has 10 more Stat Points in every stat but speed, so it is better. Both Pokémon have the same movepool, typing, abilities and stats, so Rhyperior is better due to its higher BST. However, Rhyperior is obtained by trading a Rhydon with a protector, so if you can't do that Rhydon works nearly as well.