Pretty well what I saw with mine in non-scientific tests. Wide open centre performance is amazing, as are the edges. The centre picks up a tick but its already so good you cant really see improvement past f4 (overall contrast rises though, giving the impression of more bite). The edges improve gradually up to f8, but there is nothing to be gained by stopping down further.
Amazing lens and at 120g, the A7/R + 35 combo weighs 100g less than the M240 body alone.