I have had a motocomp INTERPHONE headset for about 6 months now. It works. Bike to bike, rider to pillion, telephone operation and satnav voice. On a motorway we get about 1/2 mile using bike to bike, about 6 hours battery life on bike to bike, and having accidently left it on in standby mode about 10 days.
Its waterproof and the speaker and mic fit well into both my helmets. Its the best gadget I've bought for the bike.
I got mine on special at the NEC mororcycle show, but I think the normal price is about £150.
But have broken a couple of Scarla riders by using them in the rain, this hopefully will save money in the long run.
see
WWW.motocomp.com