I researched the heck out of pistols when I bought my first one, and ordered a Sig P226 in .40, and a .22 conversion. I wouldn't consider a polymer gun at all. I practiced a lot, and shot ok with it. Went to a holster-rapid fire course, and we shot much more than advertised... I ran out of ammo. So the instructor hands me his G17, and WOW.... my double-taps went from about a 7" circle to a 2" one. And I was probably 3 times faster with the thing. I put my sig up for sale right away and had a G17 by the end of the week. Later, someone at the range handed me a G36, and that thing was great! Same natural pointing, you could just look at something and put a round into it instinctively.
They're definitely not for everyone, but for some people they JUST WORK. It's just a matter of ergonomics, I guess.
I had the opportunity to go to a range in Missouri recently, where $10 gets you access to the whole rental wall. I tried the 17, 19, 26, and 30 side by side. I had been considering trading down to a 19. I had a glock-bonanza for a few hours and burned through about 6 or 7 hundred rounds. I had a total field-day there.
The 26 was a huge surprise. I found that, with the pearce grip mag extensions, it fit my hand in the most perfect way. The round hump at the back of the grip pressed right into the bony part between the muscles in my palm, and cradled between the meaty parts. I didn't have to put any focus on my grip when shooting, and I could shoot it noticeably faster than the others. The short sight radius didn't affect anything. Trying it without a pearce grip was a bit awkward, but it was perfect with one. It was also great when I used a G17 mag on it. It was such a surprise, but this was the best shooter of the bunch.
The 30 was interesting, too. It's like a fatter 19 in size, not the "subcompact" that it might sound like. It was great, but being a .45 I found it just noticeably slower than the others. Not by much, but with the 26 I could just blast away -accurately- sounding like a submachine gun. I also found that my hand didn't press up into the backstrap like it did with the 9's. It was like it would fit perfectly if I had gloves on, but there was just a bit less tension going on overall. I had been considering its cousin the 10mm G29 before this... they still interest me but the 26 overshadowed it by far.
I got to try the 19 with and without a suppressor. Wow, is a suppressed pistol ever a terrible handling firearm! The 19 was nice to shoot (unsuppressed), but I would keep it on par with the 17. I found that the right side of the grip didn't press against the lower meaty part of my grip quite the same way as the 17 does, but it handled very well.
What I got from the whole thing was that definitely all fit differently, but all seem to point naturally in the same way. Perhaps the angle of the grip is the common factor among them. It was the fast follow-up shots that showed the difference between how well each one fit. I'm confident that I could pick up any glock and get the first round on target the same way. (except maybe the 43, that might be different)
So I'm a glock guy. The only criticism I have of them is that the magazine release could be a bit more smooth and positive like the P226 one was. But then again, I've never fumbled with it either.