It looks like Spotify is still in the lead in terms of paying customers, if this chart from Statista is any indication.
The chart shows that Spotify has a handy lead over Apple Music at the moment, although it's yet to be seen just how many people buy into the YouTube's new Red service, which could change the balance of power here.
A couple things to keep in mind when looking at this chart.
1. There are only a bit more than 40 million paying customers for streaming at the moment, so there's a lot of room for growth.
2. The chart only looks at Western services, and doesn't include any from Asia, where people have been used to paying for music for some time.
You will find more statistics at Statista