Personally I'd get the PO Chrono. The Omega is a better watch, IMO.
You'll have to decide, but the Oris is a much bigger watch and much thicker too. I've had a 47mm Oris and although you could, it doesn't double as a board room watch all that well as it struggles to fit under your cuff. The PO on the other hand does anything and goes anywhere so I'd go for the PO. Funny thing is I did. I still have my PO (non-chrono), but the Oris is gone. Good luck. I honestly don't think you could loose with either.