Ted, I am not too familar with O so I don't know what is included. Will you receive airfare, tips, internet and excursions on O? I know alcohol is not included but not sure about the rest.

With alcohol, tips, excursions and internet, I would rack up quite the bill daily on O.
If you figure excursions for 2 usually runs us around $200 a day for the basic excursion, our alcohol would problably be around $100 a day (though did I hear that O is now serving wine at dinner, gratis??)
Tips I have no idea since it's been ages since I have had mandatory tipping so not sure what that would be a day and I don't know what O charges for internet, which I use quite a few minutes daily.

I guess my opinion would be, if you can afford it and after considering what the daily extras would be, I would choose the all inclusive as there were too many years when I wished Regent would go AI!!!