According to a recent DF article, the next PlayStation (PS4/Orbis) is very likely to overpower the next Xbox.
The CPU will be roughly equal. PS4 with better GPU. PS4 with lower, but faster RAM.
The specs seem to point towards a more multimedia and Kinect oriented Xbox, while PlayStation focuses on delivering power to games.
Full article: http://www.eurogamer.net/articles/df-hardware-spec-analysis-durango-vs-orbis
Sounds dreamy for hardcore gamers.