I've found the Tactacam fits my requirements best, it's just simple and straight-forward, whereas other setups requiere buying special lenses, or they are not very sturdy, etc. etc.
The SideShot is nice if one already has a GoPro to go with that....
PhoneSkope — well, if I have a cellphone to spare for only scope camming, great, but I'm not mounting my cellphone on the scope, just to keep taking it off to use it.... — way too valuable source of info, ballistic apps, maps, notebook, target maps....
Matthias