with 2 mates we all had interphone tour. Clear, and background noise OK. They were different model years but all connected OK. Auto switch to phone worked OK, if two or more of us had our satnavs linked this sometimes seemed to cause it confusion, could lose connections for 5 minutes. Range I did not think was great, but not an issue with pillion. Half a mile at best sometimes a bit iffy less than that. Supposed to be able to link 4 riders at most, there was just the three of us and OK. Also once linked it always remembered
Not tried anything else.