DA to Ultegra to 105 chain
 

Dura Ace 10speed chain weighs 280grams.....
Ultegra 10speed chain weighs 280grams......
105 10speed chain weighs 280 grams.......

Any reason to buy a DA chain over a Ultegra over a 105?

sram

They are the same chain with the exception of surface treatment. I have never bought a DA chain and can't see any reason why anyone should.

Any Dura Ace part makes you faster, regardless of its weight.

Bling, baby!

Nope.

Don't know about the CN-6600, but in my experience the CN-7801 is slightly smoother than the CN-5600 (especially when you don't lube your chain as often).

I wipe down every ride and lube every 3 or so.....

DA stays prettier longer.

Shiny coating on DA (inner and outer plates) and Ultegra (outer plates only) looks nice, cleans up easier, and doesn't corrode (and is arguably smoother, though I can't say for sure), and only costs a few bucks more depending on where you get it.

The DA 9 speed chain was on sale at Performance for $22 a couple of weeks ago. I like them better and I'll pay the extra couple of bucks (but I wait to get them on sale), but I won't try to make the case that you "need it" or it's "worth it" or anything like that. Just depends on what you like.

If you don't lube often the 105 chain will rust since it's not plated. Ultegra is 1/2 plated and DA is fully plated. Function and durability, other than corrosion, is the same.

It still amounts to paying extra for zero benefit. Ya gotta lube the chain.