Much better, if there is enough light. At night there will not be much difference, and in low daylight the older A129 will win since to the A129 Pro will have too much motion blur to read moving number plates when they are close up, it requires you read them while they are still distant, and for that you need to use the 4K resolution. It is actually not far behind on motion blur, but if you use 4K resolution you can very often read stuff you can't at 1080 due to motion blur even if it does get close enough, and even with 1080 on the old A129.
There is no good reason to use 1080 on the A129 Pro, the 4K will produce much better detail even if you use the same bitrate as 1080 on the old A129. The only issue is that when you play the video back, you need to use something that can show the full 4K detail, and if like me you use a 1080 monitor then you need a video player with a zoom function - not a problem, just a fact. I find 30mb/s is perfectly adequate for dashcam use, 60mb/s is very nice for the holiday movies but not necessary for everyday use.
If you don't mind the extra cost, go for the Pro. When you get used to 4K video, 1080 is not enough!