I also found that really hard, and now I know why - that's amazing!

Great. I was feeling good about myself for managing to pick the uncompressed one, and now I keep wondering if I just got lucky. :D

I'd argue the opposite, "voice is the hardest to get right so we chose a vocal track" -> voice is hard to get right, so they got it least right.. For me, Tom's Diner was the easiest of the lot to pick out.

I was the opposite. The classical was easiest because it had so much texture that was easier to spot tiny flaws in that texture.

Can you explain what exactly "texture" means here?

At any point, there are many different types of instrument playing a variety of pitches and melodies.