The Nokia 6 was built to the highest quality standards, as least as far as it's build quality goes. According to HMD, the Nokia 6 is made from a solid block of 6000 series aluminum, goes through two anodizing processes and then polished which results in a beautiful sleek durable phone structure. HMD also mentioned that time that it takes for each procedure, and I was quite shocked to see that it takes 55 minutes to produce the chassis, let alone the anodizing process that takes 10 hours because it goes through 5 polishing procedures.
The Nokia 6 indeed looks super sleek and this is just one area where Nokia fans expect from Nokia phones to be That being said, the phone itself isn't that different than many of the other mid-range Android phones out there. Don't get me wrong, it looks great, with its curved antenna lines following the contour of the phone, but the Nokia 6 isn't like the Nokia Lumia phone that had distinctive design and you can easily tell that that particular phone was a Nokia and not another brand.
By the way, the 6000 Series Aluminum contains added magnesium and silicon that improved its strength. The added materials makes it more versatile heat-treatable aluminum, which make them ore easy to machine and therefore easier to shape it to a certain structure this way (source). It's also said to be good corrosion resistance and high strength and this is why this metal is the perfect choice for mobile phones.
I don't know what's the difference in look and feel between 1 run of polishing or 5 runs, but I believe that with more polishing, you get a much smoother look and feel that can reflect light better. I assume that the smoother the surface is, the more reflective it is because textured surfaces reflect light to different ways and that is why you don't see a shiny reflection with textures surfaces.
I have to admit that the Nokia 6 commercial video reminds me that of the iPhone 5S and the sides of the phone do remind me the iPhone 5S one.
Here is the Nokia 6 commercial presentation.
Anyways, judging by the pictures and the trailer, the phone design looks really sleek, smooth and beautiful.