I am lucky enough to have a Glock G45 and a M&P 2.0 compact. I have only held the 19 in the shop and the M&P was a better fit for me as a compact. I did buy a 17 rnd mag for the Smith and used it with the adapter. It felt pretty good.
Does the full size Smith have the same grip dimensions as the compact with a adapter? I have large hands and there is more room on the Glock.

Yes. The fullsize guns have the same grip size as the compact sporting a 17 round magazine with the adapter. The fullsize guns are excellent. You will not be disappointed if you decide to pick one up. I have 10 different fullsize models, the 4" Compact, and the 3.6" Subcompact, and a Shield 40. You can buy with confidence.

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The Penetration Channel

Comes down to grip, ergonomics and trigger for the most part. I've never shot a Glock, but I don't care for the grip angle or the grip texture.

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Born to protect those I love.

I love the G45. Its a great pistol. I haven't owned the M&P 2.0 Compact, but I owned a 1st gen Compact, but its more G19 size in the grip. The full size M&P would be closer to the G45 in grip size, as the G45 is a full size, G17 grip and G19 slide/barrel.

Ergonomics are important. Very actually. A lot of people will tell you this or that doesn't suit them in hand, and thats great...but thats them. Its important when choosing a pistol that it fits YOU. We all have different palms and finger size combinations.
The grip size, the overall shape need to fit your grip, you need to be able to reach the trigger and controls adequately, etc. If you can't, or if most of those don't fit well, you aren't going to shoot it as well.

Most of the top manufacturers have an excellent product with well thought out layouts and ergos, and function well and are durable. So don't worry about that as much as wgats important.

After ergos, you have to shoot it well. All of them take a little practice to get used to and find their sweet spot. In the long run if your technique is good and you still can't shoot it well, you might consider trying something else.

There are people that prefer certain brands and are determined to make it work, because they want it to, or because thats what everyone else shoots, when in reality they'd probably shoot something else better.

As far as Glocks, the G26 fits me best and I shoot it best, then the G19, then the G17/45 in that order. I shoot them all well but a few better than others, mostly its the ergonomics.

There's really not a whole lot of difference in the "grip angle". It has more to do with the rear palm swell that some call "the hump" and where it fits in the cup of your palm...or doesn't fit it.
Some people like more grip to sit in the cup of your palm, subcompacts and compacts are more likely to do this. Longer grips like some compacts and full size, or full grip 1911s don't sit in the cup, they usually go all the way to the bottom of your grip.

Regardless it boils down to what fits you best and how it pulls up to your eye. You are the only one that can judge what fits you best. Only way are going to know is if you handle and shoot several.

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