Glad you're OK -- very scary video!
In terms of dashcams, Vortex Radar just published their 'best dashcams" video here:
Personally, I like the Blacksys dashcam. It's a little less expensive than the blackview with almost all the same features, and what I consider a better looking form factor (it's the one the BBmyCar guy uses -- the one in the video was pulled from his car, while all the other ones were just unboxed -- so that says something).
I feel like everyone just gets the blackview because everyone else does too. There are other options. If I didn't get the blackview, I'd probably go for the Thinkware as a close second choice.
I also have the speed disabled in my dashcam so it can't be used against me if need to use the video as proof. But also, the speed reported by GPS is very accurate, usually more accurate than most car speedometers which can commonly read +/- 5mph.