I couldn't update via the application manager (even though I had 86MB free in my rootfs, and the update only needs about 84.5MB free), and then I tried updating via PC Suite and Ovi Suite, but both are rubbish with the N900 and usually just throw errors while trying to update, so finally I managed to update via the 'Faster Application Manager'.

Now everything is updated, but besides the fact that the device seems to be running a bit faster, I don't see any difference...