I no longer own a pistol in .357 SIG, but I have owned several, still have about 500 rounds of Speer Lawman target ammo/200 rounds of Gold Dot, and am tossing around the idea of getting another pistol in the caliber (Hence the reason I haven't cashed out my ammo).
To date, I have owned the following pistols in .357 SIG:
1) Glock 31
2) Glock 33
3) H&K P2000SK (also had a .40 S&W barrel for it, but always kept it in the factory .357 SIG configuration)
4) Glock 33 with OD green frame
The G31 was always a range toy, and I never really cared much for it. Both G33's spent time as my off-duty/backup gun. The P2000SK was my off duty/backup gun for a good while.
Personally, I really like the caliber. It's got a lot of heat behind it, good penetrative ability, and with the right loads... it expands quite nicely too. I have never found the recoil of the round to be too much, although it does make a LOT of noise.
I also own/have owned various pistols in 10mm Auto, but I prefer the .357 SIG over it, as my handguns are primarily for defense against two-legged predators, and the .357 with a quality 125 grain defensive load is quite capable in that area. For me, the .357 SIG is second only to the .45 ACP.