I bought this on a whim because I've got more money than sense, I'm a closet environmentalist and I've got no money...
BUT IT TURNED OUT GREAT! It's actually a really good piece of kit, comes with a little armband to strap it your arm (or rucksack, or even your wing-mirror if you're sick of looking at all those boring cars overtaking you in the fast lane), and also a little clip to fix it to your bicycle frame too (this snapped the first time I used it, but that's more to do with my ham fists than a bad design).
My only complaints really are that it loses it's charge quite quickly (the internal battery doesn't seem to hold the juice very long), and that it didn't come with an adapter for my HTC, but you can plug in any USB charging cable, so I just used the one that came with the phone instead.
All in all, a great buy - so if you're an impulse-buyer like me, FOLLOW THAT IMPULSE!