And still, all models are exactly the same.
And now show me a comparison of the same very complex model rendered five times with instancing and without. I am sure that the instancing one will only be slightly faster, if not even slower. As I already posted before, I am not sure if I understand the concept behind instancing correctly, but if I do, it basicly means that it reduces the amount of data pushed to the graphics card if the same object is rendered again and again. Fact is, that this part of the rendering, isn´t really a big problem anymore with todays hardware. A bigger problem actually is to feed the graphicscard with enough data, so that it doesn´t have to wait for the CPU to push new data.

Btw, if I am writing bullshit, please correct me, as I am really willing to learn more.