I know you have made your decision, but I just thought I would make a comment as I have both an S&W 6906 and a Glock.
I have an original 6906 that I bought new. I then acquired several high cap magazines along with fill-in extensions that allowed them to fit flush with the 6906.
I also had a trigger job done to it and a new hammer like the larger Smiths, with the exposed part for the thumb, which I like as I like to shoot single action with the first shot when I can. I really like the gun, and consider it one of the best 9mm guns ever made. I think that is a consensus on here. They are solid, well made guns. The only thing I don't like about them is the way you have to take it down with the pin system through the frame. But it is a great gun.
I also have a Glock, but mine is a Glock 26. I know it is not a Glock 19, but I find the 26 to be the most useful of all of the Glock designs for me. I have the standard 10 round mags, plus a 12 cap, a 15 cap and even a 17 cap. I also installed the 3.5 connector for a lighter trigger pull. Then I got night sights and the Lasermax internal laser. So all in all, it is a very flexible design, with a lot of possible accessories which add to the capability of the gun. I love the gun. And it is very easy to take down. Nothing to it. The plastic in the gun is actually a feature for me, as I like its basic toughness and resistance to damage. I can carry it CCW, (even in some pockets if they are large enough), or use it for home defense, or have it in the car, and it gives me the greatest combination of toughness, reliability, firepower and flexibility. And I shoot it well, especially with the little 10 round mags for some reason.
So the bottom line is, I really like the S&W 6906, and it is a well made gun. But it cannot do what my Glock 26 can do, in regards to overall usefulness.
I also was looking at getting an S&W Shield recently, as they have been such a rave. But, having the Glock 26, I decided it was a better choice with more rounds, and I didn't need the Shield, which although little thinner than the Glock, is still a bit big for pocket carry, so it offered no advantage to me.
So what I do is keep the 6906 with a high cap mag ready for home defense, and, have the Glock for lots of other things, at least for my style. Someone else may be different, but that's me. And I feel like rich man.
