The only benefit that I noticed while on Piracetam(3200mg/day), Hydergine(9mg/day), and DMAE(500mg+/day) was better mind-muscle connection, but this only occurred a few days during my cycle. It happened while on these doses, the highest I've tried to date, but it's occurrence was very inconsistent; one day I would feel that awesome mind-muscle connection, but then another day I felt nothing.
For me, there was no smart drugs effect. After the cycle, the few days after stopping all smart drug use, I felt that my cognitive function improved, so possibly the after effect worked for me, but it may have just been a placebo effect.
According to anecdotal evidence that I've read, they improve certain abilities in some people.
My cycle was approx. 2 weeks and this may have also been a reason why there was no effect on me. Although, I have heard people mention they notice an effect the same day the start their cycle. Another reason why I did not feel any positive effect could be because my daily dose of Piracetam was too low, I was only on 3200mg for a few days toward the end of my cycle. I started with 1600mg a day.