So, it looks like the GP team bumped up Bite/Crunch to an "A" grade, with which I am in total agreement. B/SE and B/C are the premier attacking movesets, each has their respective utility.
Cool down/Recovery
Crunch 3.2 seconds
Stone edge 2.3 seconds
B/SE does about 5.5% more damage than B/C without too much effort. To come close to the damage of B/SE you need to use crunch as often as possible but the cool down of crunch is too long to be using it often. You will be very susceptible in getting hit by charge moves.
Without Dodging B/SE is better than B/C
With dodging B/SE is by far much much better than B/C
1 full cycle or 3 crunch is 9.6 seconds with zero meter gain total damage 210
1 full bar of SE is 2.3 seconds Tyranitar still have 7.3 seconds to match 3 crunch 9.6 seconds So tyranitar can spam around 28 bites. So combine damage of SE & bite around 268 plus charge meter is already 60% full.
Crunch is awful for players who like to dodge quick attacks. and the key high CP defenders are not weak to dark, so there is little benefit to having 2 dark attacks. As such, pokebattler simulations find a tremendous benefit to B/SE in their rankings. An example with all level 30 and dodge all pro is below. Note that B/SE is in a class by itself, and the rest have much more minor differences.
B/SE -- Make it through 6.6 defenders in row (higher than everything except Blissey)
B/C -- Make it through 4.9 defenders in row
IT/SE - Make it through 4.8 defenders in row
B/FB - Make it through 4.5 defenders in row
IT/C - Make it through 4.3 defenders in row
However, if you spam click without dodging, then there is little difference between B/SE and B/C with most defenders.
