Complete silence, performance beyond anything people are used to at home. Most people don't even know the choice exists, and even if you go to a bougie specialty cooking store they'll try to dissuade you from this and instead sell you on a higher priced product that doesn't work as well.
One annoyance is that almost none of the vent hood stick out far enough, ideally you want the vent hood to stick out a few inches (at least) past the front of the cook top, but almost none of them do that (likely due to head bumping issues, understandable) so a lot of effluent still escapes.
It's one of those ideas that works fine when it's just a rare thing, but if 100% of households had one I guarantee we'd see headlines like "Wasteful Exhaust Vents Burn As Much Energy As Cleveland" etc etc.
I for one welcome our fume hood inspired overlords. The nice thing about fume hoods is that they're optimized for maximum extraction efficiency for a minimum extraction volume.
Everyone notices the side walls, but an overlooked secret of fume hoods is that they extract air backwards toward the back wall, not just upward.
Makeup air just ensures the exhaust meets its rated flow rate. It doesn't reduce heating or cooling costs (if anything it increases them).