Appears pretty life-saving from the video. Curious how well it handles the upscaling/downscaling of layer styles/paths... often times when saving for 1x (after designing in retina) some manual caressing is required in order to make certain assets legible.
Yes, it’s certainly not trivial to do scaling right in Photoshop. A lot of attention has gone into making sure PNG Express scales properly (ie. non-rasterized scaling, correct scaling of slices not aligned to grid, correct layer style, corner radius & vector mask feather scaling, optional scaling of patterns and all that good stuff).
You won't find better automatic PS scaling anywhere, but of course if your assets need manual pixel-hinting for each resolution, then there's no way around that... but at least then you can still automate the export :)