For pocket carry in a holster, the 938 is a fine option in its class. As one of the few SAO options, it has one of the better triggers in its class, which makes it nicer for range use when it's not on duty. The fact it comes standard with tritium night sights is a huge advantage in its class too, and closes a lot of the gap in cost between it and other models. It's a very accurate pistol, but so are most of the pistols in its class - surprisingly so for most folks. Like most Sig models, the P938's are available in a broad spectrum of finish options, which is just icing on the cake.
I will offer my standard, obligatory, recommendation against manual safety carry pistols. In the event of a stress inducing attack, the manual safety is a liability. I prefer to carry a weapon with as few manual manipulations between, "oh ****," and "bang" as possible. The P938 is a fantastic pistol, and I have carried mine quite a bit, but it's a liability. This is the ONLY negative feedback I would offer for the P938 - it's a great example of an SAO pocket 9mm, but I don't recommend ANY manual safety pistol for defensive use.