Before I got my CZs set for Carry Optics, I shot a G19x with DPP. I can't say that my match placement differed a lot. A ton of people here use G34 for CO, but I think for many the choice was simply because they already had G34s. One of my training buddies, a very strong M CO shooter, fully prefers 17 over 34. I know only one guy who actually took time to quantify the differences in match performance, he's a member here, and while he really likes how G45 cycles, his match performance is better with 34 MOS.
As I posted elsewhere here, there are subjective perceptions how guns feel, and there are objective results comparisons. I don't really think we have much of the latter.