I think they are both good choices and I would, if I were you, try to jump behind and put rounds down range with each and see which feels better to you. I haven't added a Shield 45 to my collection yet, but my Shield 9 has been a 100% reliable companion since day one and shoots Like a duty size pistol. My G36 has also been 100% reliable and I am typically a Glock fan/fanatic. My primary carry pistol each day is a G19 or 32 depending on season, and immediately upon its release I bought a G43 to serve Auxilary/backup duty. Well I already had the Shield 9 and I shoot it much better than the G43 so I ended up selling the Glock even though I love Glocks! I own 3 Glock 19s, 2 26s, 2 17s and one each 20,30 32, 36, just to further enstill my love of the Austrian wonders. But yet I chose the Shield 9 because I like it that much more. I run the no external safety model all stock except for a set of talon grips and some nail polish on the front site post. I don't think you could go wrong with either pistol honestly, so I would try as best you can to shoot both and then make a decision. This is especially true if you are new to .45 single stack micro pistols. They're not uncomfortable to shoot, but they are a different animal than a standard size pistol. I've shot quite a few and it's totally manageable but takes some getting used to. Because if this overall comfort with the gun in your particular hands is paramount for you to get a good grip and be able to hit with the thing. Good luck!