The concept of a chase or alternate appearance figure is nothing new for toy collectors. It seems it's the same for collectors the world over, particularly for popular characters like Saber from Fate: Stay Night. If one is willing, pretty much every costume she appears in can be had. Fair warning, it probably won't be cheap.
This version is the Revoltech take on Saber Alter, who is a sort of Bizarro corrupted version of Saber. Which is funny, because in most of her portrayals (especially Unlimited Blade Works), Saber is portrayed as incorruptible.
The figure itself is quite impressive, but as with Figma figures, Revoltechs have their own foibles. The chausses (armor plates on her legs) are articulated, which is kind of a nice touch that lets her legs move side to side pretty easily. The same cannot be said for the front and back flaps, sadly. Also, one alarming feature is that her top and bottom halves are not permanently affixed. The first thing one tends to do is pick her up by the shoulders or arms, at which time her legs (which are considerably more heavy than her upper body, clatters to whatever hard surface is below you.
Saber comes with two 'hair' options, the first is her normal bangs, which is the iconic look, and gives a good view of her evil eyes and vein-ey cheeks. The second is the 'Rider-like' visor which covers her eyes and makes her look a bit more sinister and less like some plague victim.