I find it surprisingly hard to find a simple MP3 player for an iPhone these days. I mean, just a simple application capable of downloading an MP3 file locally on the device with good playback controls, simple library management, nothing fancy. Readdle’s Documents (which I know very well) and EverMusic seem to be popular options. Documents offers a good user experience, albeit its multipurpose mission with documents management.
(I’m a moderate consumer of Soundcloud (paid subscription) and use Downie to download files from the service. Those files are stored on my DS720+ Synology NAS.)
What’s your experience in playing MP3 files on your iPhone? I’m curious.