The chain on my Rune is quite slack, but there is a fair amount of growth under compression so I left it to be safe. I get a little bit of chain slap when it gets really bumpy but still not lost a chain yet. Not even when I went over the bars at the weekend.
There is a but of wear to the ring now. All the really wet gritty rides have scored the teeth, but it's still working well so I'm a happy bunny.