It helps a little bit, though mine is a cheaper version: I just use a digital timer for the lamp by my bed.
But it's definitely not something to use as the only means of waking up, unless you hook up an array of 1000W of fluorescent tubes.
I guess it varies for everyone. I'd also wonder about the whole subconscious thing. A lot of that "soothing" stuff is probably talk from people who conveniently just happen to be selling very expensive lamps.I believe it's supposed to be a subconscious thing.. The light slowly turns on and your body interprets that as the sun coming up i.e. time to wake up.
I'm not sure if a lamp clicking on will do the same thing, but maybe? I would imagine a sudden blast of light to be annoying whereas an emulated sunrise would be soothing