iAudiogate is what I use with an iPhone 6s and Chord Mojo
has a nice, clean, UI, does very well all I need and the EQ stuff I don’t need/want is there but not on your face
tried NePlayer, highly praised on Head-Fi, and trashed it: doesn’t play AIFF and doesn’t read Disc# tag, mixing up multi-disc albums (unless they’re in separate folders)