I am currently researching the difference between Cube Mapping and Spherical Mapping.

Wikipedia says the following: "In the majority of cases, cube mapping is preferred over the older method of sphere mapping because it eliminates many of the problems that are inherent in sphere mapping such as image distortion, viewpoint dependency, and computational inefficiency. Also, cube mapping provides a much larger capacity to support real-time rendering of reflections relative to sphere mapping because the combination of inefficiency and viewpoint dependency severely limits the ability of sphere mapping to be applied when there is a consistently changing viewpoint."

viewpoint dependency

how are cube maps NOT viewpoint dependent? can somebody explain?

and does this imply that pretty much in every case Spherical Maps can be replaced by Cube Maps? Or are there exceptions? (some examples would be nice)