Rank easiest to hardest opal

I'm curious... I've worked Coober pedy, boulder, lightning ridge, mintabie and some of that SA pink stuff... from this I think that from easiest to hardest:

Lightning ridge

Coober pedy

Mintabie

Boulder

SA pink stuff

I put that on the end because I haven't worked the pink opal much, but boulder I've noticed cuts at different rates because of different media in the same stone and the opal can crack when dopping.

Mintabie is fun but look at it and it will crack

Coober pedy will release big chunks of you don't manage your speed

Lightning ridge is what I learned on so I find it easiest.

What's your preference?