I bought a Mobius M800 action camera shortly after it was first marketed, in 2013. The review site Techmoan.com rated it well. The camera had excellent features for that time, and at a very moderate cost. This camera is still being sold as of 2018 and is valued for some of its features, particularly its unusually light weight, small size, low price and focusable lens. New versions, the Mobius 2, Mobius Maxi and Mobius Mini have been released. Their features are similar other than the ability to record at higher resolutions.
I would consider using this camera on my bicycle in always-on dashcam mode -- with an external power pack -- if I could get it to work again. But only on dry days...
The price is under $100 US.
the camera is small size and light, as mentioned: it is less conspicuous and puts much less of a load on the helmet than others.
Video quality at 1080 30P is excellent.
The Mobius can be used as an action camera (start-stop manually), a dashcam or a security camera with motion detection.
Even in action-cam mode (start/stop manually), video is recorded continuously with a one-second overlap between files, sufficient to avoid a jerk at the transition if clips are post-processed for image stabilization using my recommended settings.
The image is sharp from edge to edge.
The lens is focusable, making the camera useful for shots on miniature-railroad sets and the like.
Low-light performance is satisfactory for night use as a dashcam, or on a bicycle with an LED headlight.
Audio quality (mono) is reasonably good, though subject to wind noise.
A file is not automatically saved when the camera is shut off, at least not in action-cam mode. The file must be closed first. This would be a fatal flow in dashcam mode. (This may possibly have been corrected with a firmware update.).
The lens cap which was supplied with my cameras was too loose and did not snap into place.
The 720P 60 mode does not scale pixels, resulting in a reduced angle of view..
The camera isn't waterproof, and the lens is exposed and vulnerable to damage. An optional waterproof shell is available, but it eliminates the option of external power.
Battery life is only 80-90 minutes -- though the camera can run on external power through a USB connector.
There is no external microphone input.
Changing settings is possible only when the camera is connected to a computer or Android device -- also easier with a Windows PC than a Mac.
Output of streaming video is a bit kludgy through a special cable which attaches to the USB port.
I used my first Mobius M800 camera for about a year, until it quit: the yellow indicator light flashed, no matter what, and the camera would not record. I bought a second Mobius camera. After a few months, it developed increasing problems. Color rendering got weird (very blue during the first 30 seconds of recording); there were gaps between clips. Then that camera quit too.
I may try to revive the camera. Various fixes have been suggested online. Stay tuned.
Here is techmoan.com's video review, which covers the camera's features thoroughly, but does not address the reliability issues.