Ektachrome 100SW seems to be a good film with the Heliar, both through its color rendition and the not as extreme contrast. Velvia does not do very well, because it accentuates the corner falloff and the naturally greater contrast range that wideangle lenses usually encompass. After that the news gets better. The Heliar renders detail, both medium and fine much better, and at higher contrast levels than either the Contax or Nikkor. At the center the Contax and Nikkor are quite good, but still nowhere near the level of the Heliar.
Contrast is never as high, anywhere in the field.
This is understandable when you see the amount of glass that the latter two have. Similarly, the flare levels of the Heliar are significantly lower. Distortion is also lower in the Heliar, but both the Contax and Nikkor lenses are quite good in this regard. The Contax seems to have somewhat better flare control than the Nikkor, but not by a big margin. I also had a quick look at the new Tamron 14, and it too has distortion levels which make the lens completely uninteresting for me.