No cracks in my wax. Haven't dropped a single waxed wheel. (My port salut attempt did test it's strength against the forces of gravity and, sadly yet predictably, lost.) I guess the brushing very easily causes uneven surface (the one that's against the cheese) that is a good place for molds to live. That's why I'll try dipping.
I looked into vacuum packing devices, but those things are expensive. And I still do like wax, even if it seems to be, ahem, more challenging than some books would imply.
All have been dry to the touch, but don't know if it has been dry enough.