I've been taking modafinil off and on for the last 10 years now, usually with a prescription, sometimes without, and it's been very helpful. I get about 6 hours of good use out of it as far as ADHD symptoms and such, it'll keep me awake for about 8 hours.

armodafinil kicks in a little quicker, lasts longer (I can get a good 10 hours out of it, and it can keep me up for 12), and makes me sweat a lot less than either Provigil or ephedrine. I had been waiting for it to come off patent in the states, and it did over the last 2 years so now I can play with it.

I'm not going to sit here and talk about sources, but test your shit. something I got from an overseas vendor tested positive for methamphetamine once (might have been mdma, my test can't tell the difference but either way, test your shit}