Does not make sense to me. Ok for cooling,since cold air sinks, but silly for heating.

And I never heard of whistling and drafts being caused by ducts exiting at or near floor level.

If that were my installer, they would have to show me a WHOLE lot of proof for those claims.

As far as color, I like them to blend in wherever they are and paint them accordingly. I'd never want to see a nickel colored register just because the fixtures in the room were nickel because I don't want to view the register as something to notice. I'd rather it just disappear into the background visually.
We went through a lot of trouble to get our registers on the ceiling in our current build so I'm smiling at your disappointment! The "normal" way that it's done here in VA is to put floor registers on the upper floor and ceiling registers in the basement so we were making them do something that was out of the norm.

My take on this is that it's mainly for cost and ease of installation. Everyone kept telling me that it was because of the heat rising, but noone seemed to extrapolate this principle to the basement! :)

I was adamant about not having them on the floor so that furniture placement wouldn't be compromised and I wouldn't get dirt and dog hair in the registers. No wonder there is a big business in cleaning ducts!

We sized the systems accordingly to take into account the extra ductwork required. Also we were very anal about the locations in regard to ceiling lights and cans.

the hole for registers is 13 1/2 SQ and I guess that is part of the eye pop for me. I was used to seeing the standard size ones. I am sure it will be fine and what you have said about the blending in - I get that and agree. My bedroom just got 8.6 feet wider so today was the first look, it takes a bit to take it all in after knocking down you bedroom wall. Thanks for your input....and my GC would thank you too. Another issue put to rest.