We have a Zulu and 2 Bose X in our R44. We bought the Zulu because of the Bluetooth function - it can be really helpful to be able to talk to people on the ground. It works great.
As for the noise cancelling - the noise level in a R44 is no different to the Bose as far as I can tell. Both have great clear audio and are very quiet.
The Lightspeed however seems to have some problems with doors off operation. It tends to start to oscillate sometimes, which creates a low frequency sound, like blade slapping.
This is affected by how well it sits on my head at the time.
Has anyone had this experience with the Zulu?
It doesn't really bother me, I still prefer it because of the BT, and the fact that it has volume sliders instead of the wheels on the Bose.
Both are really comfortable, even after wearing them all day.