I have the 39.5mm PO in black. It's by far one of the most worn, loved, and perfectly sized (for my 6.5" wrist) watches in my collection. I absolutely love it but as you can see from other commentators, your milage may vary. Once adjusted properly, the bracelet is super comfortable and I don't find the watch wants to move from being centered on the top of the wrist. It's also the thinnest PO ever made at a hair over 14mm if I remember correctly.
Best of luck with your decision. I traded in my Speedmaster Pro for it as I always felt it was too big for my wrist and just never did bond with it. I have not regretted that decision for one second.