Hi again.

Here are some updates on the matter.

I've just visited a local electronics store which had both N9 and Lumia models, 2 Lumias, (cyan, black) and black N9.

The salesman was kind enough to show me all three devices out from the box, so I compared them directly to my cyan N9.

My suspicions were correct: there are very noticeable diffrences in surface material between Lumias and N9, and also between two N9s!

The black N9 from the store was more matte and refined than my cyan N9 and the one that I saw earlier in another store, also black.

However Lumias are even more refined, so all three instances were different - the N9 is different from another N9, and yet it's subtly different from Lumias as well.

Another interesting thing is that N9 from the store was made in Finland, just like mine N9, and Lumias were made in China.

All three models, two Lumias and N9 from the store had very sturdy body, unlike mine N9 which is creaking very loudly at the sides (and that's very common I see - so much for the superb build quality by Nokia).

So my logical conclusion is: Nokia obvioulsly updated manufacturing process for N9 at the time Lumia 800 arrived, by refining many things in terms of surface material, coating and also structural integrity (although for that I would need to test those for longer periods of time) - but they officialy denied that, which is totally not cool. That's also the reason why so many users complain for bad materials and others are thrilled.

I hope this will be of some usefulness for those who look for N9, despite the fact this market is shrinking.

Unfortunately I was not able to take photos to prove my findings, because the only camera I had was on my N9 which had to be photographed side by side with other one :-)
However I hope I'll get that chance some other time with dedicated camera.