At one time, the .357 Mag was my preferred revolver cartridge. Things have changed, and now my .45ACP revolvers are my favorites. I have a GP-100 set up with good aftermarket sights and a nice grip that I plan to keep because of its versatility and because I also have a lever gun in .357 Mag. The GP-100 shoots 158 gr bullets nicely, and that's what I use in the carbine, so it's convenient.
I like the .45ACP round in both 1911s and revolvers, and I feel it is very adequate for defensive use. It's also pleasant for extended sessions at the range. I view the magnum now as more of an outdoor cartridge for field use, and it's good to have the power on hand if ever needed.
I also have a couple of revolvers in .44 Special, which I think can go either way -- either as a good defense round or for field use with proper ammo.
I think the other factor for me is that I view the L-frame size guns as ideal for the .357 Mag, but I just really like S&W N-frames. The way they handle, the balance, that big ol' cylinder... I just like 'em.