I used to talk with people on reddit about Linux mobile versus Android. Android is really advanced for PAM and SELinux compared with anything I saw from Linux. Also the sophistication of the CPU scheduler was often talked about. Android can support asymmetry in ways Linux is unable thus far. A few months ago I seem to recall seeing a post or two about Linus okaying increased CPU scheduler complexity and asymmetry as a future target, but I have not followed up on that one. IIRC the main thing with CPU scheduler asymmetry with ARM is the core spin up and idle modes.