quality is always the issue with additive manufacturing. the quality of the metal being printed now is pretty terrible and requires a lot of post processing. sometimes even sintering, in which case it being additive, isn't much of an advantage.
on the quality of surface issue, only two photon seems to have the required accuracy to achieve something like final form surfaces, but two photon is tough, and again materials, and again time. every time you increase the quality, the process time goes up by a function of a cube .... tough to complete parts. there is also envelope size problems, and computer stitching issues.
it has its place, and for some medium scale, and low quality applications, it will be used in production. but to replace machining, esp in high accuracy/surface finish applications? nope.