My friend and i both have 20S EVO.  We tried Wave this past weekend.  At first, it seemed promissing.  A bit of lag, but still clear.

Had problems with volume between sena device, wave voice, music and phone GPS App.  some low, some very high.

The connection through wave would drop and not reconnect.  Also, it seemed after some time, wave would disconnect from searching for friend.

Also, i read that friends can be connected for unlimited distance ? i don't see him on the map when we were both connected but far apart.

With 20S EVOS, should it connect via sena device when no cell reception? and then switch to WAVE we able?

was so glitchy ended  up not using it because of that.