I like both, it really depends on my mood. I listen to music from a lot of genres. If I'm reading or writing something I have a great instrumental jazz playlist to listen to, mostly what people describe as the cafe/lounge/lo-fi style. For regular listening or while driving it can be either fast or slow.

Generally faster but I do enjoy slow music as well.

Both, depending. When I'm working, I need slow music and stuff without lyrics. When I'm walking (and not listening to podcasts), I like fast music. And when I'm just listening (actively playing/seeking music), I've got a range of tastes, and love plenty of slower songs and plenty of upbeat ones (plus some stuff that folks would probably classify as cacophonous).

I'm all about the vibes. Some days I'm feeling slow jams and other days I need something upbeat.

It really depends on the original I think.

Eg. As I was talking to @astro_penguin about it yesterday.

Iron maidens wasted years original, quite fast quite heavy, great track. https://youtu.be/Ij99dud8-0A?si=7MwkgfJOGZzBHuii

But the carved in trees cover slowed it right down and bought an entirely different perspective to the track https://youtu.be/rTZVHMP_vpY?si=a7Jw2Teg7jC14s_S

But does it work the other way? Yes, yes I think it does.

Better Midler - wind beneath my wings, beautiful, soft, slow, ballad. https://youtu.be/0iAzMRKFX3c?si=-Y8xWkdm47UxQ52a

Sonata Arctica cover more power metal ballad, sped up, different perspective again. Great version. https://youtu.be/kzapwP5Z9kA?si=ikgHcW0UscaoMqit

I think the choice for me isn't as black and white as fast or slow, it's more based on the original and the new perspective that the cover brings.

I would say slower. I think space in music is key. I enjoy bands like pink floyd and tool for this reason. Lots of space. These days so much music is just super overstimulating to me.