For me, I would go with the Glock 20. Though, the 1911 10mm holds some allure since I also have a soft spot for almost any 1911. I have given this question some thought and here is how it broke down for me.

I wanted a utilitarian workhorse 10mm. I also wanted something light and simple. It would fill the role as woods packing gun when I did not need the power of a larger caliber, and would be lighter to boot. I opted for a Glock or a 1911.

1911- cons - heavier than Glock, more expensive( but still worth it), need extra mag to meet Glock capacity(therefore more complex). Do you get worried about putting some wear on your guns( I don't mind character)

Pros- great trigger, slim profile for easier packing, 10mm 1911s are just plain cool and I still want one. Since you mentioned concealment, I would say for me a 1911 is easier to conceal since it is more slim. The Glock is one fat handgun. Maybe if I had a better cc holster for it would be about the same.

Glock cons - worse trigger, it's fat.

Pros - light weight, higher capacity in a single package.

For my needs the Glock has the advantage because it's pros have a lot of up side in its desired role. I put a lighter trigger in it and the width is not that big of a deal in open carry. I do have large hands and the Glock fits me well. But I don't know how someone with smaller hands would like it's width. I bought a gen 4 Glock 20 a couple of years ago and could not be more pleased. I have it loaded with 180 gr xtps and it is decently accurate. I do shoot it fast and well in the limited self defense drills I do. I also enjoy shooting at distance with it. 75, 100, 150 yards. I have been working on getting a load worked up for a 200 gr hard cast WFN, but no luck yet.

For me a Glock is a reliable, simple, light, all business gun that gets its done. I can appreciate it for doing a job well.

My thoughts on the 10mm as a cartridge. It is fantastic overall with some caveats. If you have a 10mm you may as well use it. This means hot premium ammunition. If you shoot regular off the shelf 10mm stuff you get .40 SW performance at a higher price in a larger framed gun. I have nothing against .40 SW by the way.

Let us know what you decide.