I've tried both 9mm and 40 S&W at the range, overall nice gun. The grip is narrow but it is kind of long from back to front. Don't know which backstrap it had though. The 9mm was a good shooter, not the most comfortable to shoot but very accurate and should carry very easy. It's no lightweight like a Keltec PF-9 so it had enough mass to handle the caliber no problem. The 40 was a pain to shoot. The narrowness of the grip + recoil of the ammo made for an unpleasant shooting, each shot felt like a knife digging into my hand. The 9mm shoots much more like a Taurus 709 than a Keltec PF-9.
The only reason I don’t own one is the price. It is a better gun than the Taurus and the Keltec, but I could purchase both instead of the PPS for the same money. Only mentioning these two because these are the ones I have experience with.