I have been using a Sena SMH10 for about 5 years now. I can use it for a full days ride on a full charge. It can pair up with 3 other units and it has compatibility with non-Sena products too. Sena's warranty policies are tough to beat, I damaged the contact pins on mine after about 1 1/2 years and they replaced it free. I've used the Sena in absolute torrential all day rain and it didn't miss a beat. Personally, I'd have nothing else.
"I tell you, we are here on Earth to fart around, and don't let anybody tell you different." - Vonnegut