I posted this short vid on another forum. The video was cut short because I was dumb enough to press the call back button while recording from my phone YouTube - Mazda 3 2010+ head unit by QualiR from autodvdgps.com (QL-MZD313)
Rear view camera only cost $20, but the picture quality isn't that great, only good enough to let you know what's around you. Night vision works amazingly well too. I definatly think it was worth the money.
As for installation. It's VERY simple, just pop out the original unit, and plug in the new one. Rear view camera was a little bit more trouble, but not as hard as I thought it would be. Mind you, I probably didn't do it the "right" way. There is enough space above the license plate (where the camera is mounted) that I can fit the wires through. The hardest part was having to strip the hatch apart and pull out the weather stripping to get the wires inside. I also had to splice the video cable to fit it through the stripping.
Steering wheel controls work great, just as they did before.
Sound quality seems better than it was with the stock imo. It also has an EQ with different presets, which is a huge plus. And you can control the volume of each function seperatly (radio, navigation, TV, DVD, bluetooth, etc.)