Both are lovely! I voted for 05 because it's deeper, and more rare. And of course that year is known for its beautiful thick leather. But as an 06 owner, I think it was a good year too!
Overall, I don't think you can go wrong in your decision, they're great colours!
I agree, if the Olive's leather is better, then clearly you want the better leather. It's an added incentive that Olive is more versatile than Origan, and in my humble opinion, a much prettier shade of green.
sorry, can't help. i can't vote, cos i like both colours and i'm not even a green person. olive is warmish and origan has a greyish tone to it that i adore. if i must choose personally, i'd have to look at my wardrobe to help in my elimination process.