My experience with 357SIG after playing around with it for a couple of years, was its really no better or worse than any of the others when it comes to shooting it and what it will do.
Cost of ammo is still pretty much relative, 9mm is still the cheapest, .45 is still the most expensive, and 357SIG and .40 are still in the middle. Availability was never an issue around here, and all the Walmarts had it , even when they didnt have anything else. Like any of the others, buying online by the case is still your best bet.
Ive reloaded a bunch of 357SIG. Its not at all hard to load. If you use a .40 carbide sizer for the first step (which adds one step), you dont need to lube the cases. With the right powder and load, you have no setback or neck tension issues. The only real downside to loading it is, you are limited in your choices bullet wise, and they are more expensive, and sometimes hard to find.
Shooting wise, I never found it to be "flashy", with factory ammo or my reloads. It does have a slight bark, but its really not as bad as some make out. Recoil is basically the same as +P+ 9mm out of the same model gun. I had a Lone Wolf 9mm barrel for my Glock 31, and if someone handed it to you, you wouldnt be able to tell the difference between the two if you didnt know what you were shooting.