To set the record straight on motion detection and motion sensor, this does not come with a motion sensor you think, i.e. infrared motion detector that would turn the camera on when someone moves past. No. It is a shock sensor. Let me explain. The "motion sensor" here is when the camera shakes (because the car got hit), it will start recording (there is a good 10 second lag for camera to wake up, FYI). I am okay with it cos I don't want it to wake up and alarm strangers every time they walk past and record them, I live in a "could be better" neighbourhood and I would prefer not to record what strangers may be doing in the neighbourhood as long as my car is untouched. So I prefer this shock sensor instead of camera turning on and who knows I will end up with a smashed windscreen and camera stolen because it filmed something some stranger got paranoid about. I set it to turn off after 5 seconds (not a big fan of recording when I am not driving) and leave "motion sensor" on in case someone hits the car it will record what happens.
Because this has both front and back cam (took me about half an hour to hide the wires: look for "How to Install a Dash Cam and Make it Look Clean" by Offbeat garage, that guy gives key pointers for easy hiding of wires with just fingers all under 4 mins (disclaimer: nothing to do with them, just an intro to a quick install).
It does not come with a manual but the options are intuitive and easy to understand and use. Somewhere in amazon this dashcam supposedly allows maximum 32 GB but that is not true. I use 16GB and it is fine, I don't drive much, data gets overwritten after 5-7 days so it is fine. Part of me wish I could get a 128GB which some reviewers say this dashcam is compatible with, but I am a big fan of robustness when it comes to electronics under constant move- smaller GB, lesser sector problems, and my memory card is specially made for dashcams (shock and heat resistant).
Last but not least, I am writing this review because I want my free gift (not gonna tell you what it is- buy it to find out haha). The gift does not require me to leave a positive feedback, but I am giving it all 5 stars because previous dash cams begged me to. Seriously the dash cam industry needs a wake up call, this cam should be the standard, I won't even call it impressive by my ideal standard of what a dashcam should have, but compared to the other offerings at this price at this moment, both the quality and value is stellar.
EDIT: Got my 16GB from my video. The video is great. Take a look.
No still videos of parked car for more than 3 min, so that is great. I tried tapping the camera while parked with engine off and dashcam completely off, and it recorded the event under "emergency" folder. I guess if someone did bump into my car it will record.
I also found out that dual dash cam at 1080p means it eats a lot of data and yes, I tried 16GB, but 16GB is too small. Learnt my lesson. Having an overwrite loop about every 2-3 days for 30 min of driving per day isn't the kind of assurance I was looking for. It was too short. A 16 GB card will store 60 blocks of clip every 3 mins, front and back so 30 clips of actual events recorded. That would mean 30 x 3 min - 90 min for a 16GB card, so 128 GB will give 720 min or 12 hours of recording before overloop begins. That would even cover a small road trip. So I got a 128GB Samsung Endurance card (5 year warranty! That is crazy) for only $40 and if my calculations are right the data will be overwritten every 20 days or so. That is a good three weeks so I should be well covered. 2 weeks into the purchase and I am very satisfied.