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.

I cycled modafinil/adrafinil and caffeine. For me it was a much stronger focus effect than caffeine and a much weaker effect than amphetamine. However, I developed an intense case of the hives after use which occasionally (1/2y) recurs without use with no prior history. This is not an uncommon side effect according to the doctor who I reported this to.

In my case I experienced no physical dependency on any of the drugs and chose to stop because I wanted to perform other experiments. I’d say it’s about half a decade now since.

I do know others who get weakened impulse control but I just get hyper focus of various degrees.

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.