Ashwagandha - has anybody had positive experiences helping with mental alertness & concentration?

Consider Bacopa. While ashwaganda (withania somnifera) is a wonderful rejuvenative herb, i prefer another traditional ayurvedic herb bacopa monnieri for improving mental alertness and concentration.
Some + data. There are some reports of this having a positive effect-i noted nothing obvious when i gave it to my father.-also no problems.