I've been taking these on and off, a half pill (100mg), or occasionally 200mg modalert brand pills and i find them amazing. I feel no physical effects from them, but i'm more on the ball, sharper, that kind of thing, also really helps me push when exercising. Its fantastic stuff, had no real sleep problems on it either though i do take them early morning if im taking em, and noticed no side effects as of yet.
The effects might be minor, but even that makes a big difference in concentration etc
Also havnt noticed any of the problems others have pointed out with the modalert brand, sometime in the future if i can i'l buy a strip of a different brand (modavigil etc) and see if i get a different effect, my guess was it was just a bad batch of those modalert pills others got though? They seem to be fine to me, though i have nothing to compare it with