PlayStation 4 Going to launch after Xbox 720

We know that PlayStation 4 and Xbox 720 going to hit in the mid of this year.
The leader of Sony Kaz Hirai said that PlayStation 4 will launch after the Xbox and the Microsoft, Because if Sony launched it's Next-Generation Console it can cause leakage of  specifications.

Now someone may say that we already know about the specification of the both consoles which are going to launch, and both companies Sony and Microsoft gives us the core ideas and their processing.

Both Sony and Microsoft are silent to tell us the actual date of releasing. They just said that it's possible during this year of after this year.

Conclusion:
PlayStation 3 launched just after the Xbox 360 and gives much success to Sony.