I've had a fair number of pocket and single stack 9mm carry guns, the one I had carried by far the most was a Kel Tec P3AT, because I could just drop it in my pocket holster. Then I tried a P238, and was sold. My wife really liked the SAS, and could run it easily, so we bought one. It's very nearly the same silhouette as the P3AT, albeit wider, and doesn't come out of the pocket quite as smoothly, but not bad at all.
I take care of the maintenance in a couple professional office buildings, and my XDS was just too much to have IWB all day long, bending over and up on ladders. I was always very conscious of it. The P238 in a Flashbang Betty single clip IWB holster, at about 4 o'clock solves that. Tucked in with fitted polo shirts, it's invisible. We just bought a second SAS, so we both carry one daily now. My nephew just bought a 938 and we shot them side by side, it's also excellent, and much smaller than the XDS 9mm.
That said, there is a large difference in size between the 238 and 938, if you're carrying it IWB or in the pocket. I'm 5'9", 175lbs, and in properly fitting Levi's or the like, you're not pocket carrying a 938 without it being noticeable. My nephew wears looser clothes, and even with much bigger pockets, the 938 was too much for him. The 238 is the ultimate tiny pistol, in my opinion. They're expensive, however they've been 100% reliable out of the box, and very accurate, enjoyable to shoot, and the night sights are fantastic.
Get one, you'll be spoiled by it. I don't plan on ever getting rid of it, and hope to pass it down to my son. I can't say the same of my plastic pistols.