I prefer SCH to be honest. I started leveling both SCH and WHM around the same time to see which one I'd like to be a healer with for my raid group and SCH was much more prefered. Even though with WHM it's fun to have a buffed SS and Protect, not to mention Eye for an Eye and Regen on a tank lets you DPS for a while too.

But SCH? I LOVE the micromanagment of the fairy and how, in lot of regular content, Eos/Selene can heal and you can straight DPS. But the shields are also very satisfying, especially when your Adlo crits. And on big AoE moves, like the primals ultimates, popping Sacred Soil and a Succor (and usually on top of a WHM's Medica II) basically leads to almost no damage to the raid group.

They both have their advantages/perks but SCH > WHM in my book.