Looks like the .pdf version of Firefly has dropped, which means the physical copies of the book should be getting printed soon. That puts it on target for the early June date that Amazon is showing.
2 April, 2014
Firefly RPG in PDF Is Available on RPG Drive Thru
Posted by blackcampbell under Roleplaying Games | Tags: firefly rpg |[2] Comments
The Black Campbell 
5 April, 2014 at 20:57
I find it cheaper to order the book through Amazon (free shipping) and then order the pdf from DriveThru than dealing with MW directly.
5 April, 2014 at 22:13
I also have my order through Amazon. Going to be doing a review soon, then following it up with an “A/B” test — running a one shot scenario, twice, once in this set of mechanics, the other in old Serenity.