Lustrates have a faster cast animation so the heal activates faster, you can use one even when you don't really need to and get away with it because you get 3 per minute (6 at the start of a match). The act of acquiring lustrates gives you mana effectively increasing you sustainability in a long fight.

I agree that whm get better pvp utility abilities, but that can be a detriment at times too. Sometimes people die when your trying to sleep things when you should be healing, if you can't sleep that doesn't happen.

I have over 2000 games played as sch and 1500ish games as whm and i can tell you from experience that sch is much easier to play well than whm.