I've discovered so many niche bands and subgenres since I got Spotify.

Same here, plus I can finally find related songs in languages I cannot read!

At least a fifth of my favorite songs look like cryptic gibberish to me, that would be nearly impossible to find as a download... I'm firmly vendor locked for that reason alone.

I do make regular exports, just in case my Spotify account ever disappears for whatever reason. That data is too valuable to risk losing it.