Just to be clear, Yukon does not make gears. They are simply sets of Richmond, Precision, or US Gear gears (there may be others in there too) in a Yukon box. I would not put the Richmond gears in the same class as Precision and USGear, so there is no way I would say Yukon is the best.
As for what to buy, spend the money on a great setup - that will make more difference than what brand the gears are.
ive never opened a box of Yukons from any vendor besides Marlin, so i dont know where ~tc~ came up with what he said there,
buy Yukon from Marlin and you will get Yukon gears