Rhyperior - Actually, he makes a good Defensive Attacker. You can take advantage of his defense, switch it in on NVE attacks, then strike with a full forced CB attack. That's probably the most effective way to use him. Using him for Speed is pointless unless you're willing to run Jolly Nature and Rock Polish (which is a big waste if you ask me). Can also be used for a Physical Wall, but not very effectively.
Tyranitar - Tyranitar is pretty godly, but has his falls on some areas. A 4x Fighting weak is what makes Tyranitar cry, but that's where Chople Berry can be used to an advantage. One of the greatest Dragon Dance Sweepers in the game, next to Gyarados. Pretty much used for Speed instead of Defense. Sand Stream can make him somewhat resistant to Sp. Attacks due to Sandstorm's 1.5x Sp. Defense bonus since Tyranitar is of the ROCK Type.
Personally, I'd pick Tyranitar (not because he's my favorite Rock lol) since he's almost unstoppable.