Great summary.This would be hard for me also since I have the Seiko and the PO GMT ( and have owned the 8500 PO). The Seiko has a TI case and bracelet, so it's better balanced (thePO GMT is better than the standard PO, but no match for the Seiko). Both are very tall, so neither fits under a shirt cuff very well. The Seiko SD may be the only watch that can beat the Omega for accuracy, to the point it is just off the chart accurate when you start using single digit figure per year. The Seiko also has a superior power reserve by 12 hours. The Omega has double the service interval and more location to get the watch serviced. Both are are very well finished, and while the Seiko has a micro adjust clasp it is starting to look dated against the latest crop with this feature. The Seiko has a neat bevel on the crystal edge, but the Omega has more variety in color choices. The omega has a scratch resistant ceramic bezel insert. I'm not a fan of the arrow tip Omega hands, and actually prefer the SMP hands. I guess if the fact that the Omega retails for 2.5 times the Seiko price does not discourage you both are solid choices. If I may add given the PO price you could almost get the MM600 and a ceramic Seamaster SMP and have the best of both worlds.