The have betted CDN tech being older, larger leader in the space vs Amazon music. (Same as why Netflix is better than Hotstar in performance related user experience) 
  
 Also there are many creative solutions implemented to cache your most listened bunch of songs.

Oh ,the 2nd point about cache was not known

You can go through their tech blogs. People passionately write about the interesting work they have done.

Product Manager

Can anyone working in Spotify confirm this.
Does Spotify consume less data to stream?

Scenario: In a 4g my Amazon music was stuck. 
But Spotify was working

Can anyone working in Spotify confirm this.
Does Spotify consume less data to stream?

Scenario: In a 4g my Amazon music was stuck. 
But Spotify was working fine.