Most of the differences between ED3 and the Classic/1st edition rules have been covered in the 5 previews made available on the Mongoose site.
Haven't touched the book yet myself, though.
Also, I can't answer the Equinox question definitively, but it seems to me like it would be run through Mongoose/Flaming Cobra, given that RedBrick is phasing out the Print on Demand model.
Of course Equinox is still a ways off... but I get the feeling it will be worth the wait!