I ride all year round mostly with a crew. The Crew all have the 1st Chatter Box and the X1-Slim generation Chatterboxes. This new X1-Slim cuts in and out as we ride and try to communicate through Florida's roads! Also, when playing Pandora radio or FM radio ,It cuts in and out ! I rather use the old 1st generation Chatter Box!
I have XL helmet, the larger insert fit perfect. It synchronizes with iPhone no problem. The charging pigtail is a little bit of a pain to tuck away, and has flopped loose once. The speakers are "adequate" quality. I wear earplugs and music/phone conversations are clear and volume is plenty. I gave up on radio reception, just prefer to stream podcasts, radio or music via iPhone. This purchase was worth it for me, as it's fitted to helmet with nothing hanging external, allows BT music streaming and easy phone conversation.
Without a smart phone app to manage controls, the Senna is proprietary and determines the functions of other audio applications. Range is dependent on line of sight between riders. Multiple riders have had battery life go bad within a few weeks. Mine has lasted a few months but is now dead.