I've only tried Kerrygold (which is Irish butter specifically) and the white label ALDI Irish Butter which is by all account I've read online...also Kerrygold.
I've never heard of "Normandy AOP butter", you'll have to enlighten me on that one.
Costco carries the New Zealand butter that's almost indistinguishable from Kerrygold. There are inevitably some flavor differences, but not when cooked and imo not in terms of quality.
I've never heard of "Normandy AOP butter", you'll have to enlighten me on that one.