The one galling failure of Google Play Music’s web app is the lack of support for gapless playback. Other than that, it just about puts the final nail in iTunes’ coffin.
iTunes is a mature product that has gone to great lengths to implement gapless playback perfectly.
G-Ear Player for OS X. This app, available in the App Store, supports gapless playback that is nearly as seamless as iTunes.
Now who wants to write a similar solution for iPhone, Roku and Windows? 🙂