Having owned both, here's my take:
I really like Sig pistols. So this is not a bash.
For competition, the Glock has two advantages.
First, with the Glock, the first shot requires exactly the same force as the second and third shots. You might train yourself to shoot your DA/SA sequence beautifully in your shot sequence, or not. To me, the DA/SA was an unnecessary annoyance.
Secondly, and just as important, the bore axis of the Sig is higher than that of the Glock, giving you more barrel lift on your recoil. So, it would take most shooters a bit longer to re-establish the target.
Thirdly, I had a unique problem. The recoil of the Sig irritated my seventh-decade-old right wrist. It took months to heal completely. The cushioning quality of the Glock Tupperware plus the lower bore angle and lower muzzle lift allowed my wrist to heal.
But that might be just me. If you're a older person, and you're going to shoot a few hundred rounds in a day, you might want to think about this.
Again, this is not a bash. I really like Sigs. But, for CCW in the summer in The States, they're a bit too big, wide and heavy. Again, that's just me. Hey, if they're good enough for Horatio, they're good enough for me.