I am running, in collaboration with ModafinilCat, a survey of modafinil users asking about their experiences, side-effects, sourcing, efficacy, and demographics:
https://docs.google.com/forms/d/1ZNyGHl6vnHD62spZyHIqyvNM_Ts_82GvZQVdAr2LrGs/viewform

This is something of a followup to the LW surveys which find substantial modafinil use, and Yvain's 2014 nootropics survey. I hope the results will be useful; the legal questions should help reduce uncertainty there, and the genetics questions (assuming any responses) may be interesting too.