I realize that the shutter speeds are different on these shots, but keep in mind that the OIS was switched on for the 10-24mm (which the 16mm doesn't have), I have a pretty steady hand, and the image quality is better in the static objects in the scene for the 16mm.
For the longest time I was a two prime fan using the 23/56 (35/85) combo. It was a great two camera set up for spot news. Now I'm finding myself leaning towards the 16, 35, 56 (24,50,85) trilogy. I'll be getting the 90 ASAP but this will probably continue as my basic set up.