Yeah it's a useful and functional stimulant, rather than anything very abusable. I much prefer it to coffee. Some brands are definitely better than others. Modalert is very harsh and strong, I only need 1/4 to 1/2 of a 200mg pill. The provigils feel a lot smoother and more nicely dosed in their 200mg tablets.
I don't take it very often either. Once every few weeks or so at the moment, but previously I hadn't had any in months. It's very unlike speed in many ways, it's very anti-social for one thing. It makes you really not want to be around people, and that's not just me, I've heard several people mention this about their reviews of Modafinil on You Tube.
Apparently the brilliant film Limitless was based on Modafinil. This explains why so many You Tubers call it "The Limitless drug", which gets very annoying very quickly, and when the 3rd video I watched said the same thing, I couldn't watch any more of them after that point due to an extreme sheep like lack of originality in all of them! It's kind of bizarre though, as the substance is nowhere near that good. It just increases mental and physical focus and energy, it doesn't make you any smarter.