Macbook AIR build quality

I know Macbook Air is built like tank with no flexing because it's made with aluminum block.
However, I must question the toughness of the said material...Is there some sort of "coating/finishing touch" on the pure aluminum material that could warrant possible wear downs in time?
From looking at the units in Apple Store, Air seemed like to get scratched rather easily on the bottom..

What your verdict? How is the finishing? Do you think invisibleShield will be a necessity?

 

If I were to purchase the MBA, I would not add the bulk and weight of any kind of "case". I own a white Macbook and I do not add to it's 5 pound bulk with a case. Of course, it's up to you but a pc is a tool and tools that are scratched or have a few nicks on them are fine. I'm more interested in how well the tool works. A case that blocked the air vents on the MBA or impeded thermal conductivity of the aluminum case to the surrounding air might just make it overheat and cause a more serious problem than scratches or minor marks.

 

It's bound to get scratched just like iPods and iPhones because it's meant to be carried around a lot. I'd just use a sleeve for it and try not to rub it against stuff.