I was just looking at that Sony machine the other day and it seemed like an interesting concept to me. Mind you, the "ES team", like they called it, was dismissed in the mid nineties and since then the ES badge has been carried by products that were not really the embodyment of the genuine ES units. So, while I have no doubt the HAP-Z1ES will be a fine machine, I am also quite sure something like a BDA-2 would have the ultimate edge in resolution and imaging.
Still, I don't think it's really a fair fight since the Sony has a built-in hard disk and plethora features, possibly streaming too, and the Bryston is but a D/A converter sou are really not comparing two products that belong in the same category.
The "1" series was something of a comeback for Sony since it has been almost 20 years since the last ultimate series. then called the "R" series but yes, the SCD-1 was a spectacular SACD player and worth having.
Cheers!
Antun