the interior units are very quiet in my experience...

What's wrong with heating air? It was the norm in every house I grew up in...

Yeah, the outdoor units are quite often not quiet. Which matters with houses on small plots very close to each other. For that reason a water-water (earth-water) heat pump would be preferable as that's much more quiet but also much more expensive.

My nose simply doesn't work with it, I get an allergy-like reaction that never stops (non-allergic rhinitis), and my wife has the same issue, and many people I know too.