If given the choice between 2 lenses of the same focal length but different f/x value, is it generally (not considering the build and image quality of the individual lenses) better to choose the larger aperture as this will give you more flexibility in terms of aperture size?
example: 50mm f/1.8 and 50mm f/1.2
70 - 200mm f/4 and 70 - 200mm f/2.8
If so, then why do people choose the smaller aperture lens instead? Larger aperture = higher cost?

Thank you

C.J.