I've standardized on the Winchester 145gr. JHP Silvertip as my carry load in .357 Magnum. There are three reasons for choosing this load:
1. The 125gr. JHP's in this caliber have an absolutely awesome reputation as "stoppers", but they are known to have penetration limitations. If I have to shoot through someone's arm to get to their COM, or through heavy winter clothing, or something like that, there is a reasonable chance that the bullet won't penetrate deep enough. The 158gr. JHP's, on the other hand, while having a very good "stopping" reputation, have an equally good reputation for over-penetrating the human torso and going on their merry way, to the detriment of anything (or anyone) behind the BG. The 145gr. penetrates more than the 125gr, but measurably less than the 158gr. - best of both worlds!
2. The Winchester round has been through three iterations of development, and has a reputation for being very consistent in its performance, whether it hits soft tissue, bone, or anything else. It also does pretty well at penetrating hard cover, such as auto glass or metal, etc. I like consistency in a defensive round.
3. It's gained a well-deserved reputation for accuracy. I've found that no matter what gun I shoot it in, I can get decent groups at 25 and 50 yards with it. Other rounds (in my experience) tend to shoot better in some guns than in others. I like accuracy.