The exceptionally good 360 and PS3 will have a negative effect on Omni and NextBox, but only to some extent. It will be hard to validate the new purchases just because PS360 are so good. The image quality, the sound, the online play experience, the good controlers... there are few flaws. It's not like going from 8bit to 16, 2D to crappy 3D, crappy 3D to good 3D and SD to HD with online and hardrives and downloads. Games will go from beautiful to reall beautiful. That said, it's more about software support. When new MS and Sony systems are launched, PS360 game production will slow down. This will help WiiU but also 720 and PS4. PS360 will probably get COD and Madden and Fifa for at least a year, but there's a good chance we won't see an AC3 or a Batman or other AAA titles. PS4Box won't face what WiiU is dealing with now. They will have to deal with the cheaper WiiU which has been on the market for a year and is probably getting its first wave of big titles truly designed for it, but that's another issue.
