I don't know why this was voted down. The A4 is very similar to the contemporary Samsung SoC and I wouldn't be surprised if the A5 is very similar to Exynos. So far, Apple doesn't appear to be getting any dramatic advantages from having their own chips, especially considering the risk of not being able to switch chip vendors.
The A4 is very similar to the Samsung Hummingbird. The A5 isn't particularly like the Exynos, though, except in that it uses A9 cores; the A5's GPU is _much_ faster.
I think the one big advantage of having their own chips is the marketing angle. It's much cooler to say an Apple iPhone comes with an Apple A5 chip than with a Samsung Exynos chip.
I don't think customers care much about that, not even those who defended their non-Intel Macs until the bitter end.
To be more than anecdotal, the iPhone 4S site lists the "Dual-core A5 processor" as both the first bullet item, and later as its own slide.
Surprising given that tech specs are said to be obsolete. But I think it's more about the dual-core, and it doesn't mention that it's an Apple processor.
Let me rephrase: What is the main difference (feature wise) between the Exynos 4210 and A5? What technical backing does their marketing have (9x better this and 100% faster that).
The Exynos uses an ARM Mali 400 GPU; the A5 uses an Imagination Tech SGX543MP2. The latter is far faster; at least twice as fast in most benchmarks. Also, the A5 is known to have a lot of extra DSP hardware on chip, but the purpose of that is somewhat unclear for now (it has been claimed that it's to do with facial recognition, fast camera operation and/or Siri, but really no-one knows for now).
