Over the last few days I have been selling large quantities of gold to MMOfly (10k+).
They are extremely fast.
As soon as I enter Live Support I am talking to a person and I can trade him the gold as soon as I am ready. They also deliver the payment within 10 minutes after the trade.
They don't pay as high as some of the other sites, they pay $7-$8 per k usually.
I have sold more than 119k gold to them over various servers and am very pleased with their service!