"Beats Audio" is just a label, it doesn't actually support any kind of standard. And, Beats products aren't exactly known for great quality in the audiophile world, either. The sound of the phone may be great, but the label has nothing to do with it.
In the phone world, Butterfly and One (they are essentially the same) are one the best phones, besides iPhone when it comes down to audio quality. They also has headphone amplifier built in, not many phones have them.
For a true audiophile they will use external headphone amp like FiiO or Pocket Amp, but how convenient it is when you can just plug a high impedance cans and it sound good without using any external amp.