If you are considering the A119 V3, don't miss the A119 Mini, which adds Wifi and optional Bluetooth Remote, pretty much the same image quality.
The A119 V3, and Mini have a narrower field of view than the others, so plates are a little clearer, plus they have a little extra bitrate per channel, so yes the picture quality is a little better.
The others have wider field of view, which means more chance of things being visible instead of off the side of the image. Personally I prefer the wider field of view to catch more at the sides.
If you are going for a dual channel, the A229 is currently a good choice although a little new, or if you want to keep the price down and don't mind slightly older technology then the A129 Plus.
I would also like to have a rear dashcam. Any preference for that one?
If you are going for two singles, depends on if you are trying to keep cost down, but 2x A119 V3 or Mini will give excellent night quality front and back, and beat any dual dashcam. Rear quality is not as important as the front, so most dual cameras have a lot less bitrate for the rear, typically you only need to show that someone hit you, although if you live somewhere without front plates then you may want excellent rear quality too.
