The cheaper one - I've bought various things like this from Hong Kong, never any hassle, the items are identical except for a brand name. Be aware that these timers probably can't do certain things such as waking up flash units, activating AF. In theory they should be able to send a 'first pressure' signal which does both but in practice I am fairly sure they only send a single 'fire' signal. Flash units should be set not to sleep, using AC power if possible, and focus should be manual.