same goes with Android, at least with (this) SGS3.
Multitasking. works I think alot of better than with n900.
When too many applications are running (compared to the available RAM), SGS3 does state remembering SIGSTOP+CONT where maemo and harmattan tries to swap, slows down, stalls, makes me wanna reboot the device.In the advanced settingsI can tune to have max 4 background processes running rather than maximise available RAM for the foreground apps and services.

edit:
yet, I am wishful and happy they started Jolla. But I think the resources would be used better by joining the Tizen-development. Having for example good qt based essential apps for Tizen would be worth of lots of money also imho. Tizen at least seem to be getting security policy and layer somewhat well, so Jolla could adapt and assimilate it.

Choices are good, but too much fragmentation in Linux-"ecosystem" is already a problem and Microsoft is happy.