Well, anyone is free to argue anything that person wishes to argue, but about 40 years ago, after much debate and hand-wringing, it was decided by a few knowledgeable gun writers that if you could only have one handgun the 4 inch, medium frame, .357 Magnum would be the one to have.
Small enough to carry concealed, big enough to get good hits at long distance, full power ammo for certain jobs, less power for other jobs, wadcutters for practice, etc.
Even back then, the 1911 may well have made more sense as a strictly defense weapon, but the question posed was a "one gun for everything" question, and not just "what was best for defense."
The 1911 excelled at defense, and if tuned properly, at sports. On the other hand, it was not ideal for game animals. I don't see anything vastly different today that would make a duty size 9mm, .40 or .45 any better as a "one gun for everything" option.
Thus, while the M&P may very well be better for defense, it is still not the ideal hunting handgun.
And, while a 44 Magnum can be loaded to distinct power levels, the platform from which it is launched is just too big for concealed carry, in my opinion.
Therefore, after a great deal of consideration, if I could only have one, it would still be a .357 Magnum, 4 inch, medium frame.
Make mine a 686 Plus Mountain Gun, which carries like a Model 66, has a round butt for concealment, and has one more shot. Here we are 40 years on, and the answer is the same as it was in 1974.
