The main problem with Zaycev - Music MP3 is that the interface is exclusively in Russian, so most users won't understand it. Still, you don't have to know Russian to type in the name of the songs or artists you like and press 'download,' and that's basically all you have to do to listen to music on this app.
Downloading music on Zaycev - Music MP3 is as easy as pressing the download button. You can also stream a song just by tapping on it and see the album art, information on the band, etc.
Zaycev - Music MP3 is a great app for downloading music that's quickly been baptized 'the new Invenio Carmen.' And not for nothing: the amount of music you can download through this app is tremendous.