I finally entered the realm of S&W owner (my PPK/s is an Interarms) by acquiring two K-frame revolvers (a 13-3 and 65-3) over the last couple of months. Enjoying them and they are likely to be my best friends on the range, but they are not likely to be my preferred CC weapons.
For about two years I have been wanting a PPS and have started gravitating towards the M&P40C (like the barrel switch out option). It is not as compact as the PPS (nor my other gun I am considering for carrying the LC9) but it is pretty compact.
The PPS is about $250 or so more than the M&P compacts (and I would probably order one with a thumb safety). Plus the PPS seems to be problematic in the field based on what I have read.
Could stand some input on my options from those of you with vastly more experience on these fine weapons.

Neither gun is very comfortable to shoot in .40, but the M&P is the better of the two. Other than thicknest the guns about match each other in size. I would not carry a 40 with a conversion barrel for self defense, might be great for cheap practice at the range but I wouldn't bet my life on one.

I've carried a PPS 40 for a couple of years and have 900/1000 rounds through it with no problems.
Recoil is crisp but if you're experienced its certainly managable.

I own both guns but in 9mm. My personal opinion about the Walther PPS is it is a great firearm that lives up to the Walther name but I have one major beef with the design. That is the safety mechanism built into the interchangeable back strap. If your unfamiliar with this feature, it deems the firearm inoperable by removing the back strap. As a machinist I feel the pistol has been over designed because of this feature with many complicated small parts. I have detail stripped my PPS but it is not for the faint of heart. Now as far as comparing the two; both my PPS and M&P have been 100% reliable from day one. The wider width of the M&P makes recoil significantly more pleasant. But the thinness of the PPS is more concealable. I prefer the M&P over the Walther and had I bought it first I would not own the PPS. I think the small size difference isn't enough to justify more money, less capacity (7+1 in PPS vs 12+1 M&P for similar length grips), and the stupid back strap safety that could fail down the road. Keep in mind this is coming from a lazy CCWer would usually just carries a .380 Auto in the pocket or IWB. But when I do carry a 9mm it is alway the M&P.

P.S. you may be one not bothered by such things but the PPS comes with a plastic guide rod where the M&P is steel. So that was an additional $80 I "had" to spend on the PPS.

Good luck on your decision!

I would tend to think that I could not go wrong with a M&P. I like the feel, compactness and look of the PPS, but I have a feeling that I will go with the M&P when the time comes to make a purchase. I know I won't be able to afford both any time soon.

I own compact M&P's and like them a lot. I've shot my friends PPS many times and don't care for it.

The M&P handles recoil better. I absolutely hate the magazine release. It's too close to the trigger and I have to train myself all over again to remember it's there. And yes, they are too expensive.

But ultimately, it's up to you.

I carried a PPS in 9mm for about a year and own and carry M&P9c now. I loved how slim the Walther is and it's very accurate but I too was troubled by the safety in the backstrap and hated the mag release. I love the M&P9's and have no trouble w/ IWB carry with the compact.

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A real gun is a wheel gun

What about the dependability of the gun. Did you have problems with it or just was not that happy with its design after buying it. I kind of like the mag release on the PPS and I really like the single stack - I might not have to lose as much weight to carry it concealed in my current jeans/pants (:

I have not had any problems with the backstrap safety (or anything else) on my PPS but if you were to use it as intended to field strip I could see it being problematic. I figured out what size strap I liked best and have not removed it since; dry firing to field strip. Some online have reported issues with the back straps after repeated removal. As for the mag release; I too thought it was awkward at first but I did warm up to it for a carry gun. After getting used to it I find it quick and natural to use my trigger finger to swipe the release downward. I think it is a good design less prone to getting bumped on a carry gun. For a range gun I still prefer the M&P's style and location button release.

going with the PPS - waiting for a local dealer to get one in either tomorrow on Monday and will pick it up then. another dealer had an older PPS (2007 I think) for about $650. Not a good buy in my book and that same dealer said he would order one for me for about $667 (not a good deal either). Local gunsmith will charge me $560 plus tax. Not a great deal but an OK deal.