After an unfortunate event where a dash cam would have saved me from paying my insurance deductible, I installed a dash cam. The one I installed is a Pioneer VREC-Z710DH. I chose that one because of the numerous features, but also because of its second camera. One note I would make, at least about this unit, is that it is not designed for a nearly vertical windshield like the ones in a Class A. The way I installed mine solved that issue, but I would not have been able to mount it right to the windshield as most car installs do.
So far a great unit, looking forward to getting some great footage when heading out west this summer.