I can't comment on the Duchinni, but I've got a Dainese Bluetooth-equipped helmet (Performance D.Nect Infinity) and it works very well.
More info here.Sound quality is *great*, controls are easy to use with gloves on, battery life is good. It is a great helmet in its own right despite the gadgetry: lightweight, comfortable, reasonably quiet, well-vented, etc. With a Pinlock insert, it is also very resistant to fogging.
My thoughts and rationale about using Bluetooth while riding:
I'm actually a very safety-aware rider and try to minimize distractions and be very aware of my riding environment.
For phone calls I usually will not take a call while riding and let it go to voice mail, but can pull over to make one or take one without removing my gloves, helmet, etc.
It can do voice-dialling and will speak the name of incoming calls. Easy to keep your eyes on the road.
Personally, I don't like listening to music while riding except sometimes on long tours.
It is also compatible with GPS/SatNav turn-by-turn directions which sounds like a useful feature. (don't have a GPS though!)
It also can communicate with other "Infinity" helmets, but I don't ride with anyone who has one, so I've never used this "intercom" feature. It supposedly has a 400m range!
I don't think this full-face model is still available, but they have the same technology in a couple of their "Jet" helmets.