According to the Australian Institute of Sport (2011)....
An average cup of coffee or stimulant drink can provide between 30-100mg caffeine per serving.
Compare this to an average caffeine supplement (containing mainly caffeine Anhydrose) which provides approx 200mg caffeine per tablet.
We recommend caffeine as a supplement in aiding concentration and focus. It is added in ideal ratio's to many pre and intra- workout supplements to optimise your training capacity.
If you want to maximise caffeines effects we suggest taking it in moderation over the day...otherwise, you may become tolerant (resistant) to its effects.