Made me laugh, and a good idea, but completely unreliable and very annoying.
The display isn't illuminated so it's almost impossible to read at any time of day. The alarm clock resets itself every time it's used, and doesn't always go off.
You can't plug it into the mains.
But it is very funny when it does go off - the propellor whizzes around, floats right up to the ceiling and comes back down again, and if your room is untidy or it's dark it can take a very long time to find it. You need to put it back in the alarm clock to turn the sound off, so by the time you've done that you're guaranteed to be awake...
And herein lies the main problem: the siren sound is extremely loud and, well, horrible, so if you can't find the propellor straight away you will aggravate your neighbours as well as give yourself a pretty unpleasant start to the morning! It sounds like you're in the blitz. And the makers have made sure you can't cheat: there is no way of turning the alarm off without inserting the propellor - believe me, I've tried! You have to take the batteries out, which are screwed in so you need a screwdriver to get at them - even chucking the thing on the floor or smothering it under pillows doesn't work.
As someone who hates mornings anyway this just didn't help with my mood, so it's gone to a charity shop! Good luck to the next owner!