With open cockpit flying I'd be more conscious of choosing a headset with excellent passive attenuation (on top of the ANR), and having a fail-safe mode (reverts seamlessly to passive if ANR battery dies or another fault requires the control box to be turned off). Another thing to look for would be good microphone noise cancelling action which, as far as I know, is still done passively with most headsets. The individual's comfort factor is hugely important, of course.
After trying a few popular ANR brands I settled on the Sennheiser S1. In a range of different noisy environments I found the 'optimization' button to work well, and give a few extra dB of noise reduction. As far as I can tell it optimizes a feed-forward loop for different environments and if you're a purist you can re-optimize for different aircraft power settings, canopy open/closed (if applicable!), etc. The S1 passive attenuation and mic audio quality are at least as good, and probably better, than my trusty old DCs will the gell pads and noise cancelling electret mic insert.