The recent release of the Generation four Glock pistols may very well be the best Glock yet in terms of what the broadest spectrum of what knowledgable shooters want in a multi-purpose handgun.
A bold statement for sure but I've been shooting Glocks for about 20 years and handguns in general for about 45 or so. I was pretty good with a 1911 on the competitive circuit for a few decades and I think I've shot them all. And, oh yes, I sitll own a few very nice 1911 models and am well versed in their capability but given the well earned reputation, the Glock had a steep hill to climb to improve on the pistol. The Generation three pistols, generally had a single stage recoil spring, and a finger grooved and dimpled grip, with a port side only (for right hand shooters) magazine and slide release. This new breed has a dual stage recoil spring, (the Gen 3 G30 had a dual also and may be one reason it shot so well in the hands of disciplined shooters) and a reverse-able (not really ambidextrous) mag release, an enlarged and easy to operate rectangular button, while retaining the standard Gen 3 slide release. The dual stage recoil spring requires a modification to the slide to open the guide hole so it cant be dropped into a waiting Gen 3 gun.
Another addition and subtraction, I guess is that the Gen four does away with the much more ergonomic short frame (SF) grip profile on the large frame guns (G20, G21) and brings to the table only one design and that of a reduced grip frame for the large frame guns and a standard dimension frame in the small frame. With the addition of two slide on covers that pin in place with the trigger block pin (included). This allows each gun to be increased in size to accommodate larger shooting hands.
Gen 3 guns in G20 and G21 were available in the standard (large ) grip size or the SF size which is what we have now in the un altered Gen 4 guns. So no loss of my beloved SF frame though I do really like my G30 SF. I have seen a few of these Gen 4 guns and shot a few calibers of them. I have a new G21 Gen 4 and find all to be very accurate and fully reliable and expect the line to be fully the equal of the previous generation 3 guns. I shoot my G21 with the standard (smallest ) grip frame and modified it only with the extended slide stop and a 3.5# trigger connector. Glock. They just keep getting better!