I was prescribed Provigil/modafinil for a little while. At first I would take a 200mg pill and not really notice anything. At the time I was heavily sleep deprived and just kind of a mess. Then much later I rediscovered my leftover prescription and took a 200mg pill, and was floored with overstimulation and anxiety, really nasty. But I tried some more with lower doses and found that 25-100mg would make a great functional dose. It provided me with a very, very light euphoria and motivation. At 100mg I started to become stimulated, but not in a warm, friendly way, so I never raised the dose higher than that again. I found that if I mixed it with a LITTLE BIT of caffeine, like 25mg or something very small, it combined favorably and got me feeling a little bit nice. But it was very, very easy to overdo it and get disgustingly overstimulated.
Overall I wish I still had some for those days where it's hard to get going. I found it to be a very clean and effective stimulant with very little potential for abuse, and I tend to abuse things. It wasn't anything exciting, but it was nice.