This morning I started up 9 apps (Browser, meecast, 2 Android IM apps, Gmaps etc.) and have been using and switching between them all day. Not one of them has closed by itself and the phone is mostly as smooth as with fewer apps. The only tweak I've made is to increase vm.swappiness to 60 in /etc/sysctl.d/vm.conf file.

So as of now I'm very happy with the performance and behaviour! There must be something that is different between users since I've never had Jolla to run so great and others are declaring the death of multitasking