Bugs
I've found firmware issues on both cameras, with the Git1 I report them and they get fixed so I haven't actually got any to report here.
The C10, well that is a production unit and the bugs should have been fixed already, unfortunately there are a few left, maybe they will get fixed but there does seem to have been a lack of care in the development and a lack of testing, it gives the impression that the people who developed and tested it are not photographers and had no intention of actually using it themselves as an action camera.
For example, in the menu there is an option to turn off the date and time stamp that by default is placed on top of every video frame and photograph. I much prefer the default to have this option turned off rather than on, but the real problem is that when you turn it off in the menu, the date/time stamp disappears from the video frames as expected but is still there on the photos, it appears impossible to get a photo that doesn't have the date and time in large writing across the bottom of the image. Then there is the date order option, living in the UK I selected the option to put the month first, it works, the month appears first on all the photographs even though I have turned that option off, however the LCD screen on the back of the camera still shows year first and so every time I look at the screen it appears that he date is wrong even though it is correct!
Then the C10 has a lot of minor irritations, like when the screen saver activates while recording, it appears that the camera has turned off, the Git1 continues to flash the recording indicator on the back of the camera but the C10 has no indication that it is still working, the only way to find out is to press the shutter button and since that is one of the few things the microphone can hear it ruins the video! Even more annoying is when the screen saver activates while you are moving through the menu since pressing a button doesn't appear to reset the screen saver timeout!
While we are talking about testing, another advantage on the Git1 is that if you mount it on your car windscreen as a dash cam using the supplied mount it will end up upside down, it has an option to turn the image over so that everything comes out correct, it even turns the menus over so that you can still use it properly. Although the C10 does have the basic dash cam options like loop record and auto-start recording on external power, I guess they never actually tried using it because your videos will always be upside down! Even worse, for some reason Registrator Viewer is incapable of turning it over so you can't even view it the right way up on your computer. The other issue with using it as a dash cam is that the silver front makes it rather obvious to potential thieves, the Git1 can quite easily be hidden.
LCD Screen
A screen isn't always necessary on an action camera but if you want to frame your photo/video then it can be very useful, it also makes setup easy without having to connect to other equipment.
Both cameras claim to have a 1.5" LCD, however the C10's screen is a bit small for me to read without a magnifying glass while I can use the Git1 screen which is clearly a bit larger, also when used in sunlight the image on the C10 can be completely invisible while the Git1 almost always shows enough to be able to frame the image. Obviously it is not as good as a GoPro LCD which on its own costs more than the Git1 and you can't see fine detail in full sunlight but you can always see enough to know what is in and out of the image and also get the horizon horizontal.
Battery Life
On a full and reasonably new battery and making use of the screen saver, the Git1 will record for around 120 minutes (2 full hours), the C10 gives around 80 minutes and gets noticeably warmer when in use. Considering they use the same processor, the Git1 is smaller and it records files with 41% more information stored in them and it flashes a recording LED to let you know that it is still recording, the 50% extra record time is hard to believe, I did repeat the test to check!
Wi-Fi
They both have Wi-Fi for access from your phone, neither needs it since they have a usable LCD screen. Neither has an app for use on Windows Phone so since I use a Windows Phone they have both failed that test! However the Git1 does have an optional "wrist watch" waterproof remote control which is probably going to be a lot easier to use than a phone app anyway for the things you can't easily do using the screen because you not holding the camera .
Manuals
Neither has a proper manual but they both have quick start guides sufficient to let you know how to use the buttons.
For the Git1 the guide is in good quality English and although the menu options are not all explained they are all fairly obvious, most people will have no difficulty using the Git1.
The C10 guide is in Chinese and understandable English, it's adequate to get you started and most of the menus are obvious although some maybe a bit puzzling, such as "Sequence". If the menu was divided into system/video/photo sections like in the Git1 then it would be much more obvious that it takes a sequence of photos, without the division you are left guessing. Then there is "Anti-Shaking" which I haven't worked out, certainly doesn't appear to remove camera shake from videos, maybe it is for night time photography?
So what is good about the C10?
That is easy to answer - it has a webcam function, you might get a better picture from a similarly priced webcam though! Also, if you want a camera to strap to your dog before throwing a stick in the river, you will feel a lot happier about risking the C10 then the Git1, sometimes it is better to have a video even if it is not brilliant quality than to not make it in the first place because you value the camera!
Conclusion
Both cameras have so far have worked reliably, they have very similar specifications, but there is no question that the Git1 is both the best action camera and the best dash camera by quite a large margin, so unless you actually want a web camera or saving $9.91 is important then go for the Git1, even if saving the money is important, remember that you are likely to keep and use the Git1 for a long time, the C10 will end up unused because it just doesn't provide the same ease of use, fun, reliable quality of video, good looks, etc. that the Git1 does. The C10 has compromised on everything just a bit too far for it to be anything but a toy while the Git1 is a proper camera that takes good video, it doesn't have the resolution for use by a professional wedding photographer but it wouldn't look out of place and is perfectly adequate to be used by a professional estate agent making a short film of a property to put on their website, it will even do a decent job of the comentary, if they used the C10 then they would soon go out of business!
If you are going to watch your video on a 1080 FHD TV or monitor then the Git1 does a fine job, certainly not perfect but good enough to properly enjoy the results, the C10 is normally disappointing. For audio the C10 is almost deaf while the Git1 does a perfectly good job of most things and if you attach a suitable external microphone then it will do a fine job of almost anything. Neither have the resolution to do a really good job of photographs but they do both have a photo mode. The C10 does insist on writing timestamps on every photo though, even when you turn the timestamps off!
Rating
On a scale of 1 to 10 where 1 = Pure toy, 5 = Enthusiast camera, 9 = Professional photographer.
C10 fits in around 2.
Git1 fits in at 6, remember it is only 1080 resolution though.
Finally, if you want to see and hear the Git1 in a variety of lighting conditions and using an external microphone for the audio, have a look at my Git1 audio test video, I don't have a similar video for the C10, this video really wouldn't work with a deaf camera!
Youtube compressed version:
Big download of the same video straight from the camera:
https://mega.co.nz/#!goBWEKSD!ROgpZxIJmjwP7stTRcDA3gsHnV38KjKFxc8DMtCRy0g