bought a set of these scala q2 multisets..(one box has two sets).
anyways, here are some tech bits:
bike to bike - 500 m
talk time 8 hours, standby 10 days, fm radio - 6 presets.
bike to bike works fairly well, however its activated by speaking louder into the boom mike. its not just a 'line of sight' voice connection, you can speak to your fellow rider around a bend or after a turn. perfect for instruction, or chitter chatter with your riding partner. i havent tested this with other 'sets' of Q2s.
install was ok. if your helmet's neck lip is not removable, you will need to used the supplied double sticky tape. otherwise, a hex key screw connects the backing to the module. the bluetooth unit is removable for recharging.
this particular set does not come with wireless headset to connect to your ipod or other devices. it comes with a hard wire. the only bluetooth connections are phone, bike to bike, or bike to rider. i don't connect my phone to the headset, as i don't want anyone calling me while i ride.
the only downside is the fm radio isn't very good.
i paid about $160 including shipping. not sure if you can get a better deal that that anywhere. i've seen it sold locally for $400 plus, and the higher model with wireless speakers (for ipods, etc) is $500 plus.