With respect, Glock added a changeable back strap in response to consumer demand. That is the same reason they decided to offer chamberings in 9mm as well as .357 Sig., .40 S&W, 10mm and .45ACP. Again, that is the reason they offer adjustable sights, extended slide releases, compensated barrels, etc.
The development of the G-17 marked a sea change in handgun design and manufacturer as pivotal as Colt's development of the percussion revolver or Smith and Wessons first cartridge firing revolver. It combined a number of elements into a single remarkable design that immediately signaled a change as pivotal as when the Stg-44 was developed and produced.
The Glock design has proven itself to be well suited to a broad spectrum of the handgun buying public. For those who have always loved the 1911, the grip angle requires some adjustment. But then the 1911 grip has been modified with various main spring housings, grip safeties, extended magazine and slide releases, enhanced sights, etc. Yet a straight plain as issued Jane 1911 has in the hands of many proved to be a very excellent design that needs no real improvements to be imminently usable. The exact same can be said of the S&W K,N and later L frame revolvers. No one is thought to be extreme in stating that the 1911 pistol or the S&W K,L,N revolver design are anything less than a superior developments that eclipse prior efforts. In exactly the same way it is not extreme to say that the Glock pistol is a superior development. Not all Glocks are for everyone. But within the broad range of Glock pistols available just about anyone can find a Glock pistol that is very well suited to their needs and with which they will be very well satisfied.
The foregoing is not intended to disparage the M&P series. It may be that the M&P series may ultimately figure as significantly in S&W history as their various revolver designs or their development of the .38 Special or their development of the .357, .41 and .44 S&W Magnums. I hope that is the case. It has been most disappointing to see a once fine American firearms manufacturer floundering. Hopefully S&W will again move to the forefront of handgun design and manufacturer. I for one would be glad to see the Glocks, Sigs, HK's, FN's and Beretta's, etc. of this world put in a position of having to keep up with an American firearm manufacturer whose designs and production exceeded expectation to the point that the only fitting word by which to described the result would be "Perfection."
I regret that some took umbrage with my earlier comments. I personally am very impressed with the Glock design. I am very pleased with my results using Glocks in 9mm, .45ACP and now .40 S&W. The manner in which I wrote served to express my own views. What I wrote was informed by the tone of earlier comments regarding the Glock design. What I wrote was not intended to be unkind. Sincerely. brucev.