Approach with caution. The products coming out of this research at the moment (e.g. foc.us) are run by quacks. Just like those energy drinks that contain neurotransmitters (first-pass metabolism anyone and the blood-brain barrier render them useless), this is highly unlikely to cause any improvement in memory, reaction time or general cognition in the healthy individual.
tDCS and rTMS are blunt tools that broadly excite and inhibit the underlying networks by disrupting neuronal local field potentials. tDCS may be effective in treating diseases such as Parkinson's where there is a deficit in the modulation of a specific brain area, but this is wholly removed from enhancing a healthy subject's cognitive abilities, particularly when the electrodes appear almost randomly placed.