Much like Horse Traders, if you can swing it so there are no cards to put back then it becomes a real terminal Gold. KC/TR, Golem, Hamlet, and Black Market can all help with that sort of a thing, though it's a very particular kind of deck to set up.
Mandarin seems like it would be good for Double-Tactician, but if you want $8 you have to play 2 villages, play 3 Mandarins, put 3 cards back on your deck, and still have Tactician and an extra card left. Pretty hard to set up.
Mandarin is sort of like Inn, Warehouse, and Cellar, in that you need to be very aware that it shrinks your hand as you use it, so that even if you can theoretically chain them, you'd better have some heavy draw if you want to pull it off.
