Seriously, I never thought I would say that, but I think the OII is a pretty good deal for the price.
I see a lot of people on H-F rolling dynamic cans in the 300-500$ range and never being satisfied. They lose money in the process and end up buying different cans for different purposes. If they want to buy the really high-end dynamic cans (K1000, HP-2, L3000, R10, HE90...), they have to pay the same price or more than a used pair of OII. Sure, the electrostatic amps cost a lot of money, but the good dynamic amps also cost a lot.
It may not be the same for everyone, but with the OII, I don't feel the need anymore to buy another pair of headphones. It covers all the genres of music that I listen very well, it sounds realistic (for headphones), it's incredibly detailed, it's comfortable and it scales well with good equipment. I have not heard the R10, HE90, and L3000, but at the prohibitive prices they sell, I'm not interested.
Anyway, all that to say that the OII rocks.
