Tablet decision..

So I'm looking really hard a Nvidia Shield K1 tablet.
Problem is I can't find one in stock anywhere, like anywhere.

How comparable is an Asus Zenpad S, with the Intel Atom Z3580 processor and 4G of RAM? ( 64G storage/9 on amazon)

I think the Shield is what I want but if the Zenpad is a pretty close comparable I might be persuaded that way.
Is there any tablet that compares well to the Nvidia in that price range of 0 ?

thanks