I don't have a PC9, but I have been carrying an older P12 alloy for quite some time, and find it to be tough, accurate, and reliable, unless I allow it to get dirty, then she has trouble feeding.
If yer wantin' lightweight an' compact, ah love my li'l Colt Mustang for a "minimal carry". If I have my say about it, though, it'll be my High Standard1911 Crusader Compact. They ARE kinda hard to come by, though....
The PPS is a good idea. I actually owned one last year for a couple months. It was a First Editon 9mm and was a great shooting pistol. I liked it. BUT, the First Editon "special" finish started peeling off so I ended up sending it back to S&W. They offered me a new black PPS to replace it but I decided on a refund and went with an XD instead.
I want something compatable with a Crimson Trace laser grip so the PPS is out.