Trutrac is the best , simply genius they use a worm gear so the gear angle lock with power & unlocks with axle feed so it is never sticky in corners & always lock with power , it also uses no clutches so there is nothing to wear out .
Lockers are notchy , old tech
Sure grips came in 2 varieties
Cone & clutch
Auburn is a cone , as the cone wears it eventually bottoms out bcoming ineffective
clutch type are far stronger & have replacable clutches on both sides
Both have to overcome the grip to corner