To say it simple, it is bad as you want it to be. If you want clean looking shots at very high ISO, then yes, it is very bad.
But you could also turn this into something positively. Instead of moaning about how bad it is above certain ISO, just think, hhhhhmmmmmm I will get noise, how can I make it work in my advantage.
Personally I do not find noise to be a problem, I know it is there, so I work with it. Also when I know there will be noise, I won’t have any billboard sized prints made. I will just print smaller (even on a A3 print when you hang it on a wall and look at it from your couch, the noise won’t look bad. And isn’t that what it is about, and not look with a loupe just to proof a point that there is noise).
This set is made during a dance show. Shot with a K-7 under less than ideal lighting conditions. Some shots were at ISO3200, and atleast 1.5 stops under. But it does bring out some mood because of this.
Podium westland - a set on Flickr
This set mainly has long exposure shots. And I find that noise is not an issue at all, pretty clean shots.
night time - a set on Flickr