It also boosts the priority of threads that get woken up after waiting for IO, events, etc, as opposed to being CPU bound. Which I guess Linux's fair scheduler also kind of ends up doing, even if via an entirely different mechanism (simply by observing that they used less CPU).

It's interesting how different operating systems take completely different approaches to their schedulers. Linux seems to try to make quite sophisticated schedulers, trying out very different concepts, but keeps the scheduler very seperated and "blind" to the rest of the system. Meanwhile Windows has an incredibly simple scheduler (run the highest-priority runnable thread, interrupt it if its timeslot is over or a more important thread become ready, repeat) and puts all the effort into letting the rest of the kernel nudge priorities and timeslot lengths based on what the process or thread is doing.