Eames EA 117 office chair  

Hi Lily - Good choice, nice...
Hi Lily - Good choice, nice chair. However, you have already answered your own question. While the chrome finish looks good, with prolonged wear/knocking on desks etc it can start to scratch and chip/flake. The polished finish is maybe a little more durable but does dull over time as you say. Either option is nice, commercially in this day people probably prefer the chrome option although the purist will go for the polished. Good luck.

Not so fast
If the Vitra chairs are made like the HM chairs, the polished aluminum may be a bad choice, too.
The arms of the Miller produced chairs are coated with clear plastic. This was a nice detail that made the arms feel less cold to the touch, but over time, chips off (especially where the arms hit a desk). Where the plastic peels away, the arms turn a dull gray from the oxidation of the aluminum.

To be honest, I have had way...
To be honest, I have had way over 100 Vitra/Miller alu group chairs over the years and both are fairly hard wearing if your a reasonably careful owner. They are most prone to wear on the front and top corners of the fabric/leather (again due to knocking). The arms should hold up well with a little care when moving the chair around a desk/wall for example.

And
While the raw aluminum can turn dull grey when left alone it can easily be kept bright with a little bit of polish. It's only tricky if the chair is left alone for a long time and the whole thing patinas. Although some people find that a lovely look too 🙂

Oh
I agree
If people want a new looking chair they should just buy new
I love these chairs when they've seen a bit of life- in either finish

Mine is brushed alum.
I think it is dated 2002?
It still looks fresh.
I do like the soft patina over the chrome.
Though nice that the choice is offered.
I would think, if i had to decide today,
a much more difficult decision would be the
seat style...mesh, fabric, or leather?
The mesh is a very modern look, but looks a bit tired
after 8 years. Leather should go the distance?
I have also had adjustment trouble. My desktop
and lap-tops sit on stands a bit high. My old steelcase
zips up and down easily. This one does not go as high.
Or as easily. I've got it full height (i think), loose
tension, lean back, work boots resting on two of the feet.
I plan to switch it to the home.
Back to the original concern, with all the abuse at work
the alum still looks new.

I've placed my order!
Thanks for all your replies. Much appreciated.
After 2 visits to the Vitra showroom in London I'm going for the polished alum finish as I think it's just got the edge over the chrome in terms of a more classy look and will age that bit better. Placed my order today. Can't wait for the chair to arrive.
Lily