This video is 1080p at full screen if you have a big enough display (make sure you have HD selected); you really need to see it at this resolution to appreciate the differences properly.
Kodak 500T (5219), Fuji Eterna 500T (8573), Fuji Eterna 500T Vivid (8547), side by side comparison 4-perf Anamorphic. I exposed all of the stocks at 500 asa and they were processed normally.
I have always favored Kodak stocks because i consider them to have a finer and nicer grain structure and better colour rendition. It is clear however that these new stocks from Fuji have adressed these issues and i think there is little between these stocks now. The Fuji Vivid is a brand new stock that aims to produce very saturated colours and deep blacks; a bold move in the modern world of film scanning. Fuji demonstrated this stock to me recently with a theatre projection of a film print; the stock did indeed show very strong and well balanced colours with deep blacks and very little grain. What these results show from my point of view are that Kodak still seems to have a slightly finer grain and possibly a little more separation in the blacks whilst retaining very good colour rendition. The differences are however very slight and i am sure it would be very hard to tell them apart once they were graded properly.
The ultimate decision then comes down to price. Fuji have always sought to sell their stocks cheaper than Kodak, and producers inevitably favour Fuji for this reason. Now with such little difference between them the onus is on Kodak to drop the price as choosing Kodak is now very hard to justify as a DP.