Sounds like it's better for you than Adderall but I wouldn't want to take it purely to work harder / faster / better. Unnecessary, prolonged brain chemistry modifications sounds scary, and the 'no negative mental side effects' theme from the marketing is BS (from 10 min of Googling).
Indeed; modafinil has quite a few side effects, at least according to a quick Wikipedia check (https://en.wikipedia.org/wiki/Modafinil#Adverse_effects) (and while Wikipedia isn't the most reliable source, at least they bothered to cite their claims, so I'm more likely to trust that then some unfinished marketing site).
Depends on the jurisdiction. The site is based in Canada (at least according to the TLD), which doesn't classify it as a controlled substance. The U.S., however, does classify it as such and therefore disallows importation unless you have a prescription.
Interestingly, adrafinil is completely unregulated in the U.S. (IIRC), and is sufficiently-closely related to modafinil that it basically has the same effects.