I would concentrate on the Yucatan Peninsula including the Gulf and Caribbean if I were you.
And I would do exactly
the opposite. I'm a confirmed Pacific-sider.
The important thing though is that, as pointed out, there are big differences between all the magnificent beaches of Mexico. The folks from Australia need to let everyone know a little bit more about what floats their beach experience.
Then they, too, can discover that Hound Dog has inferior taste.