From what I understand, a member early on bought a SENA. Others followed suit and the SENA became the default for the club. For recommendations, for full function units, the 50R & 50S seem to be preferred. However, SENA just announced new mess units with fewer functions (voice commands deleted) for $199 vs the 50 series $350. The new units can be pre-ordered on Revzilla. In any event, just make sure it’s a SENA mesh-enabled unit if you want to talk to the group in motion. FYI – the Cardo units generally get better reviews than the SENA, but both companies have proprietary mesh systems that will not talk to each other.