MCG (Markus)
3500
Good question!
They are really quite simmilar in many ways - and in others the aren't at all... 
If you would like to afford it - go for both...
Anyway, I would go only for the sportier Patek. The hype around this watch is not as big, as around the RO, what I like.
At the end it is a very personal decision...
No matter what decision you take - You will have fun with both of them...
Are these watches sufficiently different to justify getting both??
Have basically decided to get the AP Royal Oak 15300 (white face) early next year, but since going to Basel I have alos generated a serious interest in the Patek 5167. I feel that the Cal 3120 is a more interesting movement to me than the 315 in the Patek...