Honesty and Integrity
This is a simple as it gets to be good in all respects: two talented performers, great song choices to cover, just perfect voice and perfect guitar.
Willa Mamet is the daughter of playwright David and she apparently and understandably doesn't like to make much of this which I totally get but it seems also understandably interesting, so I have made a little. She has a wonderful full vocal with a pure tone. It isn't easy to describe more other than saying it is always beautiful, and for example she covers Joni Mitchell's River superbly. Miller plays expert acoustic guitar that is never flashy but always adept, and he provides a solid fit with his vocal harmony [though goes solo on The King of Broken Hearts].
The song selection is stellar, some of which are:
Forever and Ever, Amen
Dimming of the Day - a truly gorgeous cover
No overdubs. No double tracking. No effects. It has all the honesty and integrity of Jeremy Corbyn.
There, got that in.