Upstate SC here, so I understand hot summers and the need for supercaps in our dashcams instead of a battery. The Viofo "A" series cams have turned out to be very good dashcams with frequent firmware updates, new features added, and good customer service whether through these forums or direct. The A129 Duo is looking good right now overall, and should likely be as good as the other models PDQ. Street Guardian's SG9663DC is also well worth considering and IMHO is an even better cam overall. Great customer service and firmware updates. They are also close to releasing their "Dual Remote" cam which will be a game-changer in 2 channel cams. The Blackvue 900 isn't nearly as good as their 750 and may never be. Firmware updates are slow with them and many issues go unaddressed, but right now they have the best parking mode. Waylens has potential but I hesitate to recommend any newcomers to this game. Dashcams have to perform the hardest job under the worst conditions compared to almost any other cam, and to make one do that well takes a lot of knowledge and experience. Garmin is trying, but hasn't yet learned one very basic lesson in this game: many places are too hot for batteries and your dashcam should never shut down unintentionally ever no matter how hot it gets. The BV 900 is having similar heat-related issues, and neither one will ever get better until they switch to supercaps. When they do, then maybe they will be a good choice for us.
Plate capture is never a certainty with any cam, especially under less-than-ideal conditions. With a good lens, the correct sensor and processor for the job, and well-developed firmware devoted to getting the sharpest images you've got much better chances with this. None of that comes cheaply or easily. Some experimenting with telephoto lenses shows a lot of promise here, but those lenses also make for a narrow field of view so they should not be your primary cam. The A119 does about as good as good as you can expect with this, right up there with the Street Guardian cams. Blackvue only reaches this potential at slow speeds. Plate capture is the "Holy Grail" of dashcams, but might be a bit over-rated. In most situations, all you need to have is proof that you weren't at fault, with enough details seen to show how all the other cars involved acted too. In a hit-and-run, getting the plate can help find and prosecute the offender, but what affects you most in the end is how your own insuracnce company handles the crash. And nowadays a lot of cars here where I live have stolen plates, especially ones from other states, which makes tracking the driver nearly impossible. So yes, lets get the plates if we can but let's not worry too much if we don't because we can still prove everything else.
Many good choices out there for us today, and some not quite as good but OK overall. Low-light vids are better tham ever before by miles now. That's a lot better than things were even 5 years ago when I began getting into dashcams. It does make for harder choosing, but it also means you're more likely to get a good cam which does not disappoint. And with all that you can now get it at lower prices too. IMHO, none of the "premium" brands offers the value for the money that many mid-level priced cams do. Why spend 2-3 times as much to get at best a10% gain, with that gain being only in certain areas and not others? It's your money to spend so do as you wish but don't believe they hype that those cams are so very superior when they really aren't. See the vids and hear the comments from actual owners who have had the cams for awhile. Read these forums about the issues which have been found and what has been done to correct them. Learn for yourself, don't just blindly follow along with anyone no matter what others do or say. Just don't wait forever for the perfect cam and remember that any cam is better than none as long as it works.
Phil