The old one was ugly and hard to use.
The new design is more consistent across all platforms (iOS, Android, Windows Phone) which is nice. It also looks like they have made some significant improvements in terms of performance on mobile devices compared to the old version. This should hopefully make using the app a lot easier for people who are running older devices or those that dont have great internet connections (e.g., students).
They removed several features from the app that I used quite often: My List and My Favorites are gone
https://t.co/Plz9GSzdOz