Fastest isn't the best. If it were there wouldn't be so many making lateral moves from one regional to another. I'm sure there are several that have done it that would vote against it. There are many quality experiences out there that will teach you valuable lessons you'll never learn flying 121. I don't care how many hours someone has there are still things they'll learn from instructing. Also if you want to be a shear badass just fly 135 freight single pilot