It seriously depends on what you're talking about.
The method that uses the least number of moves is the optimal sequence.
Take a look at Dan Harris's Fewest Moves Challenge. A lot of people use a variant of Petrus method. I, when I still had time to do something like that, used what's known as a 2-gen method: 2x3x3, orienting edges and permuting corners, and then finally the rest of the cube with solely 2-gen. It certainly does not work efficiently for a speedsolving method.