Using Interface Builder to create a Visual Effect Blur View and Vibrancy, I'm not seeing what I expect when running on a device. In the simulator, however, it seems to be fine.
In a new single view application project, I drag onto the storyboard the new (to iOS 8) object "Visual Effect Views with Blur and Vibrancy". This creates a two-view hierarchy where the child is placed in the "content view" of its parent (Vibrancy checkbox is enabled in the Attributes Inspector pane for the child view).
From what I understand, anything placed within the content view of this child view should have the "Vibrancy" effect applied to it.
I've placed in two copies of a PNG logo. One in the spot for vibrancy, and one at the top-level of the view hierarchy. When I build and run to the simulator, everything works as expected. Only the first logo (inside the content view) shows the vibrancy effect. When run on the device, this view completely disappears and only the opaque logo at the top of the view hierarchy remains.