Honestly, SCH is amazing in all content.

Raids, Dungeons, Solo content. To top it off, you have a Pet aiding you with free heals and abilities. It's an extremely powerful class in the right hands despite having an easy means of getting to know the class from the get-go.

AST is a iffy class at the moment. You can make it work but SCH just makes the same case and it does it better. If AST receives buffs to its cards and it's mana sustain, I think we'd have a nice alternative to SCH as an off-healer.