On 11/3 I received my DR750S-2CH (16GB SD) that I bought on Massdrop for $ 299. It was shipped on 10/20, taking about 14 days to get to Hawaii. This is much better than the DR650 I bought from them in May. It took almost 30 days to ship to Hawaii. When Massdrop ships to Hawaii, they hand it off to FedEx and FedEx logs it and passes it over to USPS who move it via Honu.
My plan was to install a pair of Blackvue's so my S has 360 degree coverage. I moved my DR650-2CH to the liftgate window and connected the secondary camera to the right rear quarter window. The DR750 primary is mounted on the windshield with the secondary camera on the left rear quarter window. Unless you are looking for the secondary cameras at the quarter windows, they are not visible since the glass has a factory tint. There's been a run of bad guys in the SF Bay area breaking into S's at the rear quarter window and stealing stuff from the trunk. Yes, my two secondary cameras are vulnerable to break-ins. But I will take my chances.
The DR750 cameras are much better video quality. Both cameras now are Full HD. And the front can record at 60 fps. The power cable connection and the camera to camera cable are the same for the DR750 too. If you are moving from an older Blackvue such as a DR500, 550 or 650, its an easy upgrade. But the front camera mount is larger diameter and you must use the mount that came with the DR750. The secondary camera mount is simply the same as older versions.
There's been some comments posted in several places that the DR750 is larger than the DR650. That's not accurate. The diameter of the body/tube are the same at 1.5 inches. However the mount for the DR750 is thicker than the DR650 so it looks larger overall. I even reported in another place that the 750 is larger and I was wrong before I measured both.
Special note. Before you mount the DR750 primary on the windshield, be sure to take a picture and/or write down the info on labels attached to the end of the body of the camera. The info is on labels next to the QR label. The is where they are now posting the SSID and the unique password for the DR750 and product serial number. The default password used on the DR650 and older does not work now. These labels are easy to ignore or overlook, then you will find yourself removing the primary camera to get the info later.
I am very pleased with the difference between the 750 and 650. I will watching Massdrop for the next buy of DR750's and pick up another. When I get the second one, I will swap out the DR650 and sell the 650 on ebay. When I bought my 650 on Massdrop I swapped out a DR550 and sold it on ebay for 80% of what I paid for it on Massdrop, three years ago. Time to do it again.