The Exynos 5 Octa is Samsung's ultimate overkill of big.LITTLE. It's 4 ARM Cortex-A15 cores and 4 ARM Cortex-A7 cores. The 4 "little" A7 cores will be active during most uses and sip power, but when you fire up a game or something the 4 "big" A15 cores will kick in and deliver performance superior to the Krait cores in S4 Pro and deliver superior battery life to the S4 Pro because most of the time the 4 "little" cores will be active.
Hopefully Samsung, the only company which can design the entire phone from the SoC to the manufactured product due to their complete integration of semiconductor manufacturing, device design, parts sourcing, and ownership of their own factories, can keep heat under control which has been such a huge problem for S4 Pro based products like the Nexus 4. There's a reason why Samsung can design a device like the Note II which manages to contain a bigger battery, bigger screen, and even a stylus inside and still be thinner and lighter than the Nokia Lumia 920 and the HTC Droid DNA (Butterfly). It's because when you are fully integrated from top to bottom like Samsung is, you have much better control of the entire design and manufacturing process.
Samsung is the only SoC design company which also manufactures their own silicon, everyone else depends on TSMC, UMC, or GlobalFoundries. So Exynos 5 Octa is basically Samsung styling on everybody because they have a better manufacturing process than the contract foundries do (though like everyone else they are far behind Intel) and they can throw 8 ARM cores on a die and not even give a fuck. Combine that with the ARM Mali-T607 GPUs and this is going to be a monster SoC. It must be nice being Samsung sometimes.
Judging from the Nexus 4, I would say not much has changed.
/rimshot