User blog comment:DoctorAsawa/The Perfect Jungler (Or Somewhere Close)/@comment-108.172.56.143-20121023220455

"Olaf's skillshot slow is one of the hardest to master, and he's better at chasing down running champions."

Please explain this point here. The projectile moves very fast for a skill shot, slows on hit, pierces through all units, and has a free refresh if you touch it. Other then mana starvation early, what problems might one come across with mastering this skill?