Astral Perception is a lovely place to be, but not always practical. It's an extra action in the holy-crap-fighting!-moments that some of those low-IP folks cling to like velcro and your Grandma's sweater, it opens you up to spirits hovering on the Astral, and it sure-as-heck messes up your real-world judgement (dice pool penalty for other stuff).
Against mundanes in poor visibility, is all kinds of awesome for spellcasting and seeing one's way about, for the most part.
My poor, squishy Chaos Mage is getting in the habit of fielding a Watcher or two just to keep eyes out for magical/astral presences (watchdoggin').
And I agree that Direct Combat spells are awesome fun. I like that Power Ball is so...indiscriminate. EVERYTHING in the area (if thresholds are exceeded) takes the kaboom.
PowerBall: when you positively, absolutely HAVE to kill every m#*$f#*$n thing (that you can see) in the room...accept no substitute. Half the calories of Fireball, none of the smoky smell.