I have the Scala Rider G9. It is my first communicator so I have nothing to compare it against. Long battery life, bike to bike intercom, FM radio, Ipod connection, voice activation, phone calls, quality speakers, easy to wire onto helmet. I know this is not new technology but it is new to me and I love it. In my opinion the Scala is awesome (but not cheap).
I've just bought the Sena SMH10 twin-pack. So far I'm happy with what it does. It doesn't do FM radio but then neither do I. It syncs to my Garmin GPS and the phone and I can talk to Jan on the back without.
Yep i got the dual pack and use it to communicate with my wife. We can both listen to the same music and talk as well. Its a great system and you can buy extra speaker and mic kit to install in several helmets.