AF inconsistencies are my biggest bug bare with lenses.
Think I'll stick with my 50L which may be softer wide open, but the AF nails it all the time every time.
Bodies: 5d mk iii, 60d
Primes: 24L 1.4, Sigma 35 1.4, 40 pancake, 50L 1.2, 85L 1.2 ii, 8mm fisheye, lensbaby, 100L macro.
Zooms: 16-35 2.8 ii, 24-70 2.8 ii, 70-200 2.8 is ii, 120-400