You are seeing alot of bias so far, so I will give you the facts.

Astro can handle all current content fine, but there is reasonable worry for savage Alex. Their heals and mp management is slightly lower than the other healers. Not a huge difference but over the course of a fight the parse does show this. They have one powerful emergency heal (have personally done 10k with it) but only one, 40 sec CD. The biggest thing I would say is its quite hard to carry mistakes like I used to on whm in DF groups.

In most content I have been parsing as astro much better than the sch's I've run into, and that's including their fairy. But I believe this is more of a skill problem, skilled sch's are few and far between, but the good ones will trump astro by a good bit. Whm are truley a powerhouse right now, in Alex fights lately I've been around 1400-1500 HPS on astro where whm are 1500-1800. Sch for has been around 1000-1100 (300 being fairy) then whatever shield mitigation added in.