I like 357 SIG, it's what I carry.
The recoil is snappy but not unmanageable. It is fun to shoot. It is very accurate and flat-shooting for a pistol caliber.
As far as defense performance, I tend to agree with those who say there is probably not a huge difference between 9mm, .45 ACP, 40 SW, or 357 SIG - all else being equal, they will probably all do the job about the same. I have read of law enforcement agencies that tested multiple calibers and chose 357 SIG, citing better performance after penetrating intermediate barriers like car windshields and door panels. Not sure how that translates into usefulness for citizen self-defense. The main reason I carry it is that I like the gun I have that shoots it, and I shoot that gun/caliber combination better than any of the others I have.
There may be a feeding reliability advantage in having a "tapered" shape round going into the chamber.
The only disadvantages I can think of to 357 SIG are:
1) higher cost or harder to find practice ammo (solution: buy practice ammo in bulk from Georgia-arms.com "canned heat")
2) decreased mag capacity compared to 9mm
3) depending on manufacturer, there may be bullet setback problems if you are chambering, unloading, rechambering, unloading the same cartridge over and over again, as some folks do with their carry piece. Then again, you can get setback in any caliber from doing this.
4) if you are a reloader, 357 SIG brass does not size well without lubrication. I usually use a light dusting of spray case lube, and it works fine.