Modafinil is basically nothing compared to other drugs. Like you will go a longer time before feeling sleepy but it's not even on the level of caffeine for stimulation. It doesn't give you much of any wired feeling, you just are less tired when you normally would be.

For many people, modafinil stops being effective as a performance enhancer pretty quickly (days to weeks of daily usage), and withdrawal is basically a few days of excessive sleepiness, so most people don't have an issue with it. Narcoleptics take it for years, mostly without issue, so it has a decent safety profile.