Before I order a new chain for my road bike, I have a couple of questions.

Can i use a SRAM chain with Shimano Dura Ace transmission kit? If so, which 10 speed chain is recommended?

Are all Powerlinks the same?

Will a Powerlink work with a Shimano 7801 chain, which is the chain I am replacing?

Ta!

in my (minimal) experience, powerlinks work with pretty much any chain of the right width (or rather of the correct designation in terms of 8sp, 9sp, 10sp etc) and any suitable width chain works with the transmission

That's on shimano-based systems, no idea about campagnolo spacing

I suppose SRAM do a 10sp powerlink; I know KMC do

The SRAM 10sp powerlinks are meant to be single use only (unlike the 9sp/8sp ones), ie. they'll do up once; don't know whether they'll come apart again though. The KMC ones don't have this disadvantage & seem to be fine (have a 10sp one on my road bike, & rumour has it that KMC make Shimano chains anyway.

Andy