For holy priest I'd suggest going Aldor because for one the shoulder enchants are better for holy priest, they have damage and healing while the Scryer ones are for crit. It's likely that you'll replace any gear you get from either faction so I place more importance on those little bonuses like the shoulder enchants that whether or not there's cool gear from either. Also, what professions are you? There are different formulas for professions available depending on whether or not you are Aldor or Scryer and you might want to take that into consideration too.