Long time reader, first time poster...I'm going to preface this post by saying that I am not pulling for either platform to be a clear winner, I am going to purchase both because gaming is my hobby and both will have exclusives worth playing.
This forth coming console 'war' won't be decided on stats alone, Microsoft, for better or worse has much more they can gamble on their console winning. One of their chips that they have played which I haven't seen discussed here is the fact that Windows 8.1 and the X1 will have exclusive rights to future (directx 11.2 and beyond). I see the first few years of this cycle going like this: developers make ps3/xbox 360 versions, they make a PC version which gets ported to next gen. Here is a quote from DICE:
Frostbite 3 Supports DirectX 11.1 API Faster GPU/CPU Performance on PCs and Xbox One
Now this is the interesting bit, DICE confirms that the Frostbite 3 engine supports DirectX 11.1 API as revealed by DSOGaming.
We use DX11.1, there are some optimizations in it (constant buffer offsets, dynamic buffers as SRVs) that we got in to the the API that improves CPU performance in our rendering when one runs with DX11.1. This will be in BF4.
This means that PC and Xbox One versions of Battlefield 4 would be more optimized than PlayStation 4.
The API's in the beginning will be a huge player in early next gen content regardless of power...even though there has been comments of SONY's libraries being better developed these are the same software engineers who couldn't make cross game chat in their last OS. Developers have been programming next gen(beyond ps3/360 capability) content on PC's for the last 6 years and they have been doing it with directX as the primary library.
They both have their strengths and they both have their weaknesses, they both will have gems that will most likely be titles developed exclusively for their respective console.