i own a DC 10-56XL anr, and we have a Bose X and a Lightspeed Zulu in our R44. All three are great headsets - the Bose is small and light, the DC would survive a nuclear bomb (and if not, DC would fix it on warranty!), all three are nice and quiet. But if I had to choose one out of the three to keep, it would be the Zulu. More versatile than the Bose, sturdier, less plastic, and I far prefer the volume sliders over the wheels on the Bose.
Bluetooth is a great feature.
I don't see why a phone call would be more distracting than a radio call in flight - of course you need to use common sense when answering! I wouldn't try to discuss my tax return during an autorotation, but being able to phone your destination and tell them you'll be landing in 5 minutes can be quite handy.
And you can always leave it off, too.
The Bose and the Zulu sound slightly different, but I wouldn't say one is noisier than the other. The Zulu wins for me because of it's features - if you don't care about them, then pick the one that feels more comfortable on your head.