Claimed to be the world’s smallest DV camcorder at just 5.5cm, it can record 60 to 90 minutes of 640x480 (2-megapixel) video on the supplied 2GB Micro SD card or use up to an 8GB card for longer record times — and you can get three hours recording per charge. To use while riding, you’ll need the extreme sports pack (£19.99) or the pro handlebar mount (£29.99). When it comes to playing back, audio doesn’t come out too cleanly, but video quality is very good for an £80 item. Useful for filming group rides or miscreant drivers on your daily commute, the Muvi’s more than just a toy.
I have one of these and it's been very useful. It's extremely lightweight and easy to use. You just have to remember to stop the recording before you turn it off, otherwise you use your recording. One criticism is that it's slow to charge and slow to download the recordings.