facebook .... I want to know the others app too
Facebook is still not "instant" for me on the 920 when resuming. I get the "Resuming" message for about 2 seconds, and it resumes where I left off. It's not as instant as Android or iOS, or even the same as the multitask card.
EDIT 1: Sometimes I get the "Resuming..." message and sometimes not. I'm not sure what conditions cause that message to be displayed yet.
EDIT 2: It seems if you return to facebook immediately after hitting home, then you'll get the "Resuming..." message. However, if you wait for a couple seconds (say 15+ seconds) before returning, then you DON'T see that message. It's a bit strange, and I would have preferred not to see the resuming message at all regardless of how quickly I return back to facebook.