Without knowing the exact target size I can't make a precise measurement. Even so, I guessed and here is what I found:
Something is wrong in my measurement guess because the holes are not the right size. Still, what really matters is center to center so, this is close enough to compare the targets.
There is not enough data to show a statistically significant difference. The XD was closest to the center. The Sig had the smallest group. Even so, none are different enough to say one is better than the other.
There is a phenomena here that I'd like to explore more though. That is the upper right most shot on each target. On each target there is one flier up and to the right. The consistency of placement is almost surreal. All of the targets have this one shot and they are almost all in exactly the same place. Drop that shot and the groups become dramatically better. Almost 40% smaller if that shot is tossed:
Even when that shot is dropped, the results don't change though. The XD is still closest to the center and the Sig is the smallest group. Of course if you ran this again, they are all close enough that I couldn't predict which gun would give the best result.