This pedometer works well, but only if you restrict your activity to walking in good light and have a good memory for key sequences.
The device is working all the time because there's no option to pause it - if there's any movement going on it registers it and this includes the motion of a car/bus/tube train. The only thing you can do to make sure it isn't registering spurious miles is to zero the thing before and after every non-walking journey, which of course negates any idea of accurately clocking your accumulated steps during the day. I suppose that you could take a pencil, a piece of paper and a calculator around with you so's you can record these fragmented readings, but this isn't something that you should have to do having spent so much on what's supposed to be a smart device.
The display is hard to read in poor light, which can be a pain, plus the casing is made of very cheap plastic that scratches/crazes very easily, making reading the display even more difficult - given that it's recommended that this pedometer should live in your pocket, generating scratches is an inevitability.
On top of the aforementioned problems there's the matter of ergonomics - this has to be one of the most unituitive electronic devices produced in recent times. There are just two buttons and controlling the thing reminds me of those dirt cheap watches that require you to memorise long and short key press sequences involving clicking one or other, or possibly both of the two available buttons. I still can't remember how to use the memory function...
So, to summarise: my advice to prospective buyers is, don't bother. To Silva, my advice is, 'get your finger out and think about the practical limitations of a design before moving into manufacturing'.