So I was in the same position as you regarding choosing a new dashcam. I wanted top end and was considering the Blackvue DR900S-2CH and the just launched Thinkware U1000. I also heard the new 4K Viofo A129 Pro Duo was coming this year.
Personally I say don't bother with Blackvue or Thinkware. I'd go with the new 4K Viofo A129 Pro Duo. After heavy research on all top end models I ordered the A129 Pro Duo this week.
I viewed the raw footage from my friends DR900S-2CH before purchase this week and it looks very much the same as what was posted in this thread. It's just not that good. Why pay $900 or so for image quality like that? It’s a dashcam - it's number one priority should be image clarity and unit reliability. I also hear the DR900S overheats in hot weather. My friend tells me his Blackvue has shutdown on those hot aussie summer days on occasion.
All of that put me off the Blackvue honestly. I really wanted to like the Blackvue. Had my eye on it for a while. Also looking at the Thinkware U1000, I don't think it's image quality is that good either. Not as good as the 129 Pro Duo in my view.
You said you viewed some footage in the A129 Pro forums. Was it this from Nigel?:
Viofo A129 Pro Dual Dashcam - 4K Front + 1080 Rear The dash camera we have been waiting for, a 4K version of our favorite A129 Duo that records real 4K at a decent bitrate, and works at night! There are a few people with early versions of this camera now, so here is a thread to post your videos...
dashcamtalk.com
I was seriously prepared to but glad I didn't spend $900ish-AUD on this Blackvue or the Thinkware U1000.
I ordered from a Viofo authorized reseller on Ebay Australia. They have it 15% off till this Sunday 20th October with free overnight shipping. Well worth it, especially with the discount.
Anyway my views on the matter. Hope you find something that works for you.