I read 3.4B transistors for the ps4, and Microsoft claimed 5 billion transistors for xbone.
I think the 5B number included pretty much everything bundled with the console, which includes the Kinect 2's dedicated microcontroller (and maybe the RAM too?).
But with the whopping 1.6B transistors required for the eSRAM, it should be a safe bet to say the xbone's SoC is larger than the ps4's one.
It's safe to say it has more transistors, but if those 1.6B transistors are crammed into the same area as 500M gpu logic transistors it becomes a bit more muddy.
<edit> much is the word I was taking issue with from DJ12s post. I expect them to be within 10% or so.