We have no sims, so this is all we can really draw conclusions on atm for level 100:
Castigator is probably a tad higher on ST.
CS is a tad stronger for dnd cleave.
If you have high crit and low mastery, go castigator. It's probably a tiny bit stronger.
If you have low critical and high mastery, go cs. Same thing...Probably a tiny bit stronger.
If you have a good mix of both, pick what you want. If you hate one particular talent, don't pick it. The difference atm is very small.
For 110 we truly have no idea. My guess is that CS will be slightly ahead at 110 because it gains more from the artifact.