Do you have any experience with a drug called "Limitless" (Modafinil or Provigil)?

I heard a radio ad for it today for the first time. It was called Limitless, and the ad featured testimonials of people saying how it suddenly brought coherence, focus, and brilliant clarity to their thoughts. The ad also offered a free 30-day sample for calling an 800 number.

Whereas those are qualities I might wish for anyone’s thoughts, the idea of getting them from a drug sounds disturbing to me. Rather, the effects sound like an illusion that people who use certain nonprescribed substances may claim to have. They might not think any better than usual, but they may have the feeling that they do.

It also sounds similar to things that students might use to stay alert through long study and exam sessions (such as Adderall).

I looked up “Limitless” on Google and found that the name refers to Modafinil or Provigil, “a drug commonly prescribed for individuals with narcolepsy.”

Do you have any direct experience of this stuff and any comments about it?

I have no interest in using it myself, but I would like to know what it looks and feels like when someone else is using it.