Honestly? Every app I use on Android is really nice and polished. Chrome, GMail, Maps, Twitter, Slack, Facebook Messenger, Hangouts, 1Password, Pocket Casts, Poweramp, and Pandora are all completely satisfying. The worst app I have is OpenMBTA...which fails to get my jimmies rustled because it's a dropdown list and a map overlay.

There are lots of shovelware applications on Android (lots on iOS too, though), but I don't really live on my phone so I think it's just much less of a thing for me.