The sound quality in that video is horrible, and acoustics and microphones vary a lot – take any switch you know well and surprise yourself with how many videos that sound nothing like what you've experienced.
It's only meant to be the quietest
mechanical board (where Edgar Matias discounts Topre, as do I), and rubberdome boards can themselves be pretty loud – the Dell KB1421 in particular has a very lound thunk.
Here are three videos of the AEK II – notice how they all sound totally different:
Quiet volume, very smeary and very mushy sound:
Medium volume, smeary sound:
Loud volume, sharp sound:
Here's
another video, with the keycaps removed – the sliders alone are pretty sharp sounding even without the keycaps on.
Personally I'm happy so long as it's no louder than a Cherry brown (by loud, I mean perceptually: that includes spectral distribution) and has a decent force curve. The objective is for something with the kind of clean, sharp tactile force curve normally only achieved through the use of clicky switches, but without the loud office-unfriendly clicks that come with it.
