If I had to pick one right now, it would be the Glock. I currently carry either a S&W 642 or a Glock 26. Both weapons have a long and proven track record. In matters of life of death, I want a weapon I can trust. Sig is pretty new to the striker-fired game and I'm still baffled at the military selecting the p320 over more proven options and there appears to be ongoing issues with it. I think the Sig p365 is way cool in concept, but I wouldn't even consider buying one until it has been out for at least a year or two. It's internally similar to the P320, but very small with a new magazine design, so I expect there to be several bugs to be worked out.

Army's New Pistols Often Eject Live Rounds and Don't Work Well With Regular Bullets - The Drive

http://www.dote.osd.mil/pub/reports/...my/2017mhs.pdf