I also have a 512GW and the little rear camera to go with it and had it hard wired in from new. It performs very well in all conditions on both the front and rear cameras.
It was great until recently, the battery has finally died, which is rather displeasing as the thing is less than two years old and never been used much on the battery.
The issue now is, every time I start up, I have to tell the camera where I want the rear picture, left, right, etc.. I have forgotten to do this a few times now.
Today, for example, I popped to the local co-op, got back in the car, drove off, forgot to press the ok button, which is easy to do, as the camera sits behind the RVM so you cannot see it.
The result, of course, no recordings and the last recording, never finishes, as once you turn off the engine and remove the key, there is no residual power to shut down the camera properly, so the files are corrupted, and this is a problem because if you were in a crash, I suspect the recording of the impact would be corrupted too, due to having no power once the engine/power is disengaged.
Something to note too (as another poster mentioned) you are technically supposed to put a 'continuous', aka, High Endurance, class card your dashcam, the ones used for surveillance footage etc, I had a card fail, a SanDisk ultra, and made a support request for a replacement, I was told they are not obliged to replace any cards under warranty if they are used in dashcams, or any device that runs as a continuous recording, such as body cams, surveillance units etc, as this is classed as inappropriate usage and/or misuse.
I checked with Samsung, the same rules apply, as they do with a few others. The good news, these types of cards last far longer than the regular cards and are not that much more.
Overall though, the 512GW is a great camera, both front and rear work well and produce good quality imagery, and the latest Firmware improved a couple of things too, just a shame the battery is a letdown.