I'm on very fast hardware, i7-2600K, 16Gb of memory, running Kubuntu 11.04 amd64
Despite that, qemu_linux_2011 seems pretty much unusable for me.
Installing application in the emulator with ~20Mb of metadata takes ages, like minutes (tens of minutes?).
Android developers complain about QEMU speed, but honestly that is like greased lightning compared to harmattan QEMU.
The strange thing is that CPU is pretty much idle, hardly hitting 10% most of the time, so I have no idea what it is doing, it might be just some IO contention or so.
Running Angry Birds in harmattan QEMU is usable, even enjoyable, and then host CPU hits 100%, so some parts of the performance are there.
Btw. is the Scratchbox QEMU the same, or would it be better or worse?