Best place I have found for Dash cam info (go to forum for cams in development):
Dashcamtalk.com
I started looking at dash cams about 6 years ago. It's the same as most tech, where the new stuff, just about to be released, will be "huge" improvement. So, I bought a cheap, high rated for the price range, $50 dash cam, 5 years ago or so, to hold me over until that mythical super dash cam hits the market. That $50 cam is now outdated and unreliable, so I need a new one soon.
Since originally buying the cheepo, I have checked back in every 4-6 months to try to keep up on the progress of that one slow developer that is known for its quality (Street Guardian).
They are about to release a duel cam system (SG9663DR) in the next 6 months that has a remote brainbox, that can be put in the glovebox. This will make it have a minimal presence on the windshield and rear window, as well as getting the electronics out of the hot Texas sun. Additionally, most (if not all) of their cams use capacitors, which is a plus, as many dash cams have batteries that can cause issues in hotter climates.
It will might have a hefty price tag, but I will probably end up getting the SG9663DR in the fall.
As an aside, those Viofo cams that Lanx linked look to be rated highly too. There is a lot of "borrowing" in these Chinese companies, so, it looks like they copied Street Guardian's design.
Direct link to forum thread for the Street Guardian SG9663DR (the owner is very active on those forums):
Hi, Can we get an update on SG9663DR please?. I'm at the the point where i'd like to replace the current dashcam because its cheap and its shows in the support and reliability. Now I know there is a existing dual dashcam (SG9663DC) but its not cheap, its essentially £300 so a huge investment...
dashcamtalk.com