I've got two RAT 1's and a Rat 2. All in D2. They aren't going anywhere.
After seeing many mixed reviews on the D2 Ontario Rats, I bought mine in Aus 8. The reviewers I watched said the Aus 8 did just as good as their D2 and it is definitely more rust resistant to D2.
How well has your Rat D2 been holding an edge and has it been easy to keep from rusting? I almost bought the D2 version.