i assume you mean: what makes mud good?

1) stone: usually the most powerful (and enjoyable) feeling of being stoned wins here (either headbuzz or couchlock count)

2) taste: many of this years winners were strains known to have slight flavours associated with them (chocolope, kaia kush, ,and from other competitions: blueberry, bubblegum, northernberry, it goes on...)

3) smell: even if its the worlds best stone, ya still dont want to smell like you just ate dogshit. nuf' said.

4) looks: not as important, but a purple/blue tinted plant with bright red hairs is sure to draw attention of the judges

theres probably others, but you get the idea i think...