For the purposes of ADV riding, Sena and Cardo should not be considered to be rider-to-rider comm devices, as the range is quite limited on the trail vs the road – intervening terrain, trees, obstacles, etc.
I have Sena for connecting to my phone, for music and calls, and as an intercom when riding with my wife (also Sena). Other than that, I never bother connecting with another rider because a radio is just much better. 5w of analog goodness that can push out for miles in good conditions.