I bought a single stack 9 last Christmas after months of research and range tests. I had carried a S&W 442 for years. The best video I found on the topic was from Guns and Ammo on YouTube that did a 1000 round torture test on 10+- single stack 9s. Their conclusion was that only 2 were flawless throughout the time and that the PPS from Walther was the best shooting pistol, if expensive, that was flawless. Well, that was when they were $550ish, and they are now $350ish regularly, so price is no longer an issue. The 2nd and 3rd (perhaps in the wrong order) were the Taurus 709 Slim and Glock G43. They did mixed loads in the same magazines for feeding and reliability - all three passed.
PPS was best all around, best shooting, and "felt most like a full size pistol". Since I have never been able to shoot a Glock worth a darn the choice, after shooting each, was very easy. PPS with 6, 7, and 8 round magazines, slim, carries well, shoots great, eats any ammo, and I love the M1 version with the paddle release (the M2 has the US button release if you don't like paddles).