It is much better than Spotify for the following main reasons:
The app is more stable and doesn’t freeze or crash - this is very important for me. It is really annoying when Spotify freezes, and takes a long time to close the app and re-start, and this happens often.
I find the collection of music is greater on Google Play.
Its quick and easy to use - my songs are downloaded and available offline all the time. They don’t suddenly disappear like on Spotify.
Hope this helps!