Song has an extensive and very good selection of music. I was surprised to see all of the different types from pop, techno, disney, country, rock, oldies. Even a huge selection of latin, my favorite. Viva Celia Cruz!
Besides the types, there was a large number of songs in each type. You could scroll down 2 or 3 screens worth. It kept we occupied for a 2.5 hour flight that turned into a 5 hour flight due to bad weather getting out of Tampa and a weather re-routing to JFK this past Sunday.
Also, who was the guy who recorded the safety briefing. Passengers got a kick out of it and it kept everyone's attention.