I've got both Bose X and DC 13.4x headsets, plus an after market ANR set in my bone dome: they all have their good and bad points.
In a high noise environment (helicopters, I know.....) the DC has better passive attenuation, requiring the anti noise to drive "less hard". If you are on battery power, this will give longer battery life, but they still don't last very long in our environment: between 4 and 20 hours, depending on aircraft type and type of operation. Bose seem to last a lot longer on battery, but can't cope with a really high ambient noise. The Bose sensing microphone is on the outside of the earpiece, whilst the DC has the mic on the inside of the earpiece. To sort out the Bose when it gets out of phase, you put your finger on the outside mic sensor, whilst on the DC you have to lift the earpiece away from your head, to allow the software to sort itself out! The helmet has very good passive attenuation, so the after market unit is very good, except that it has a slight volume difference between the earpieces, which can't be fixed.
The DC doesn't like a heavy 4 per rev beat from larger helicopters (takes ages to settle down), whilst in the same machine the Bose copes fine with the 4per, but won't attenuate the wind noise from the window seals
The DC's are (relatively) passenger proof, but the Bose are quite flimsy in comparison, and the pax just
love tying the flexible mic boom into pretzel shapes
So, there is no "one size fits all" ANR headset, IMO. I suggest that you try to borrow one of each type available, and try them in the type of aircraft that you most frequently fly, then decide. Not easy to borrow, but better than investing heaps in an ANR unit that isn't up to what you want.