I think that the gears are for the amount of water you want- so the top gear is going to give you a lot of water as opposed to first gear.So is 1=cold and 4=hot? It looks really sweet, not like the usual trash you get.
I wouldn't say no to it. Then again I am a sucker for modern industrial design.
I could easily imagine me burning my hand everyday as I shift my way up to top gear while doing engine noises.