The PO GMT is 43.5mm, not too far off from the Rolex Explorer II at 42mm. Don't get me wrong, I love Omegas and I have a moonwatch. Why don't you try both out at a dealer that happens to have both in stock? At least you get to make instant comparisons. From what you have written so far, it seems to me that you already have a watch in mind. All watches are good watches, what most of us here are trying to say is...before you spend serious money on watches that may not retain value, go get one that does first. Good luck and wear whatever you finally decide on in good health, and please post pictures of your purchase so we can share your joy...
DC