I have used Adrafinil and Modafinil occasionally for years. Adrafinil was the "original" or first version of Modafinil/Provigil. Adrafinil is supposed to be harder on your liver, and Modafinil is supposed to be a little stronger. I have used both, and really couldn't tell much difference between the effects of either. It is definitley a major improvement over any amphetamine based stuff. (I did some "old style" amphetamines, like dex, back in school studying for finals, but would never touch that stuff now - the bathtub meth that is all over these days is horrible stuff - it really fucks people and lives up).
Both do have a moderate tolerance building effect for most people, but it levels off, and is not nearly as bad as amphetamines. It has no effect on blood preassure, also. Unless you take too much, it won't get you amped like amphetamines. I WOULD NOT recommend using it on a daily basis, but it is helpful occasionally when you wake up tired and have to be sharp that day at work, etc. Do not take it late in the day - it WILL keep you awake. I find that it usually has a duration of effect of 8 - 10 hours, depending on how tired you are, and how much you take. As far as taking it to get you up for a workout, I really don't think it would help much with that, and it does last for awhile like I said above. It makes you alert, but doesn't get you pumped up (again, unless you take too much, and thats a bad idea.)