JHop: i was thinking for BIG.little the a7's would be scheduled to operate if the os or sw does not require maximum IPC (such as graphics intentive games, etc) and thus operate at a lower voltage and freq, therefore saving battery. but yeah, unknown how complex this arbitration code is going to have to be to make this happen. would be silly to use an a7 to just do background processes i would think... but i definitely will have to do more reading on it. As for qualcomm S4's being cortex A15 like, qualcomm plays a different strategy being an ARM architecture licensee. they have to develop something and use for a longer time since they have to recoup development costs of making such a SoC rather than using ARM's IP directly. as Anandtech put it, their ARM like cores are usually hybrids of previous and future generations. But for day to day use i'm currently assuming/hoping they are comparable. I've always owned HTC phones with qualcomm SoC's and in the back of my head i always feel like when new ARM chips come out i'm kind of slightly behind. for example my sensation has an ARM cortex a9 like processor. but ARM's cortex a9 processors are slightly newer in the development cycle so the geeky side of me wants the best performance 
i know the samsung's exynos with it's cortex a9 is most likely a more powerful processor. again, in day to day use, it's questionable how different things are between SoC's. hehe
I meant to say 2nd half, not 3nd half in the towards the bottom of my last post, lol. But as for the BIG.little, I read that the A7 core will only be active when the screen is off, so it doesn't have the stronger cores operating (atleast one of them might be active at a low freq.) when the screen is off. But we'll see once the test comes out how it compares to TI's M4's and others implementations.
As for Qualcomm, hopefully they wont stick with Krait for too long, because thats what gave ppl a bad taste in their mouths the past year because they stuck with Scorpion (A8/A9 class) for too long as others passed them up (mainly in the GPU side of it). The CPU held up against the other A9's, but the GPU was getting beat. Plus other things I don't feel like remembering, lol. But now, the tech fans are praising (which is funny after all the hate in 2011) Qualcomm again with the S4 release, and they rather have it over Tegra 3 (since its A15 class [strong CPU], 28nm [battery sipper/saver], and the GPU [Adreno 225] is on par with Tegra 3). But I suspect Qualcomm will be alright here on out. The CPU should hold up for awhile competing with other A15's, and Qualcomm has their next gen GPU coming in the 2nd half with the next S4, so they'll be fine in 2013, just hope they don't get comfortable like they did before S4.
As for the Sensation, it was because of Sense 3 and its low 768MB of RAM. Sense 3 was bloated. Sense 4 is more lightweight, and I think I read its code was rewrote and cleaned up. Another thing is the drivers that go along with the chip. I remember playing with the Tmo SGS2 and Amaze 4G. Both had the same S3 and same RAM. Samsung's TouchWiz UI was choppy, but the Amaze 4G was very smooth. The reason was Samsung didn't have time or was lazy to code the drivers and TW to make the UI smooth over the Qualcomm S3. The regular SGS2 with Exynos was well written for the UI and the chip. But that was mainly because Tmo wanted their SGS2 to be 42mbps HSPA+. Exynos 4210 maxes out @ 21 mbps HSPA+ (which isn't bad), and S3 was the only chip at the time that reaches 42 HSPA+. So Samsung had to make TW compatible with Qualcomm's S3 chip, but they probably didn't have enough time, or was lazy to optimize the code/drivers for the S3. I don't blame them really since they don't normally use Qualcomm SoC.
Sorry for rambling so much,
