Satin is just that, a satin finish. Lots of paralell lines from an abrasive rubbing in one direction across the surface. The finish is generally very fine and somewhat glossy (depends on exact method used). The satin finish on Busse knives run from spine to edge as opposed to the length of the blade, this is the most common satin finish on factory knives, as running them the length of the blade generally requires a good deal of time and effort doing it by hand.
Double cut is a variation on bead blasting. It leaves a very fine matte surface that's smooth to the touch and is light grey/silver in color. This is probably my favorite finish, it's not rough like regular bead blasting, holds oil nicely(gives it a pretty sheen and also helps rust prevention, not that infi needs much of that) and I have a thing for bare steel instead of coatings.