They are two very different types of watches. I would suggest going to the shops and trying them both out. I love the PAM 292 Ceramic. I tried it on, and it somehow was not a fit that I would call, comfortable...Don't get me wrong, I still love it and think that it still is a very very nice looking watch. Maybe because of my small 6 1/2 inch wrist.
I had previously owned an IWC 3706 which I loved and regret selling, but then the 3717 came along with a way sexier bracelet and a bigger 42mm case. So this I have kept for the last 7 years. Be it with a leather or the steel bracelet, this watch is comfortable to wear. Aesthetically, it suited my wrist a lot more than the 45mm PAM.
I would say, go try them out, take some wrist shots...go home, compare and see which one sings to you more. Both watches have good history and good movement. While the IWC is more "versatile" in terms of wearing a suit, or in jeans or just shorts and slippers. The PAM is...IMHO just a little to big to wear with a suit. But the ultimate choice is, which looks better on you and feel more comfortable wearing. Good luck and please post some pictures up when you decide which is for you.
DC