I have found that the Oregan Aero Hush kit works just as well as any ANR and it is much less expensive. You dont need batteries either!!
If your flying a B212 or any other 2 bladed medium or heavy, the blade slap interfers with the seal and you lose a lot of the noise cancelling capability regardless of which ANR system you purchase. A good passive systme is best for my dollar.
At least you are working on a long term solution to avoid hearing loss...good luck with whichever system you choose.