Why choose? I have all three of those primes, plus the 50 and the 85/1.2, along with the current 24-70/2.8 and the 24-105/4, and choose the appropriate lens for the job. The f/2.8 zoom is very good even wide open, though not as good as the primes stopped down to f/2.8. The primes wide open show a lot of longitudinal chromatic aberration, along with purple fringing, plus they are one major PITA to nail perfect focus. But when you do, the images can be just stunning. By f/4, all the lenses look great.
I pick the lens based on several factors, including convenience, the desired "look," weight, and absolute image quality. Usually convenience wins out, sad to say.