So, I'd say ISO 6400 is good enough to use for full sized images, whereas with the 7D, I'd tend to limit myself to ISO 800-1600. ISO 12800 and 16000 are easily usable for web-sized shots. How much this changes when using a proper RAW converter instead of in-camera JPG, remains to be seen.
These are straight from camera, a bit of a crop on Bran's image (the black one), default camera settings. Both with the kit 18-135mm STM.
7DmkII - ISO6400 by namethatnobodyelsetook, on Flickr
7DmkII - ISO6400_2 by namethatnobodyelsetook, on Flickr