Actually TAF gave me some headache 2 times for now. but its rare..
i have gone up over 100mcg without a headache.
it depends on your current state of the brain. never use TAF after a big party.. or when you have allot of things on your mind(tasks and problems)
this is where TAF knocks my head off.
btw i find TAF very useful when designing something.
it really helps me through the creativity part.