Imho beats headphones don't sound good. The bass is ridiculously overpowered and distorts nearly constantly.

Now, tastes are different, and you might want exactly this experience with that distorted bass.

If you create both the music and the speaker, like Dre does, and you wanted that experience, the right approach would have been to add such a distorted bass to your track during mixing/mastering, and then create headphones that faithfully output this signal.

This would ensure that you could enjoy Dre's tracks with that distorted bass on all your music equipment, like with your home hifi system, and if you used the beats headphones with other music, it would also output that other music truthfully.

So it becomes a bit of a standards issue. It's as if a very popular computer displays brand made displays where pixels that are 100% white will flicker wildly, but the displays brand was created by a guy known for his lowpoly wireframe art style, and this particular style looks great on those displays. So that combination might be fine, but you cannot use the displays to faithfully assess other images, really.