I currently have a PPS and previously owned a 239. The PPS is much lighter and thinner, so it is much easier to carry, IMO. In that regard, there's simply no comparison.
I found I can shoot the PPS more accurately with more rapid follow-up shots. In my experience, the 239 had more muzzle flip but perhaps a bit less "push back" recoil, if that makes sense. I also feel the 239 is not quite so well-balanced as the PPS, which combined with the muzzle flip, made it harder to get back on target. It was definitely slower getting back on target than the PPS. In my hands, I also felt the standard 239 grip was a bit too long and thin, although you might feel otherwise.
The PPS did take about 150 rounds to break in before it functioned perfectly. I had a few (one every 20 rounds, maybe) FTEs early on, but none in the last 100 rounds. Better quality ammo seemed to help, too. The Sig was perfect from day one, out of the box.
I wouldn't mind having another 239 but my favorite, go-to gun is my .40 PPS, hands down. I would trust either pistol completely, but prefer the PPS. As always YMMV.