I just bought the Beats By Dre yesterday after owning the Sennheiser HD 380 Pro and HD 595. Both of these cost $200-300 depending on where you buy them from. I bought the Beats By Dre for $300cdn taxes in.
So...after hearing about how overpriced, horrible sounding these are what did I think? Well I came to the conclusion that most people that actually downplay these headphones simply haven't owned them. They may have tried it at the Apple Store and automatically assumed that they don't compete with their AKG's, Beyers, or Sennheisers. Audiophiles typically buy headphones and then let them burn in with their setup for 100+ hours, yet for the Beats By Dre, nearly everyone on Head-Fi assumed they were trash.
They were wrong.
I listen to mainly rap music. The Beats deliver lows that you couldn't possibly imagine. I can feel actual levels of the bass and it's not distorted or over exaggerated at all. There is a clear extension and phenomenal detail in the lows. For bass, it's just no competition. My Total Bithead Amp helps the Senns in bass, but it still can't compete with the Beats by Dre, unamped.
In MOST songs, I found the highs to be superior. There were some exceptions in songs where it was more classical type of music, but I found that the vast majority of my songs presented better highs with the Beats By Dre.
Mids? Generally, I found the HD 595's to be superior in this category. The mids are definitely more noticeable and detailed in the 595's over the Beats By Dre. Not to say the Beats By Dre aren't desirable, but they're somewhat inferior to the 595's in terms of mids.
Soundstage: This is the the one place where the Beats By Dre lacked. Because my HD 595's are open ended headphones, there is definitely a wider soundstage present. This isn't anything due to the quality of the Beats By Dre. It's a closed headphones vs. opened one. The soundstage in the open one will always be superior. However, the Beats By Dre did have a similar soundstage as the HD 380's.
Noise cancellation. Many people don't need this, but I find it particularly useful in certain conditions. I've turned them up all the way and hear no "hiss". Even in environments where I'm alone, I still prefer the noise cancellation. The HD 595's are horrible in this sense. I can hear everything! The fan around me, the kids playing outside, my fingers typing on the keyboard, my finger clicking on the mouse. Beats By Dre: Just solely my music being heard.
To conclude, shop around first. Listen to Sennheiser's, AKG's, Grados, Beyerdynamics. They are all excellent options. Don't believe everything you read online. Your ears should be the ultimate icebreaker in your decision. Just make sure you're listening to high bitrate music. Most high end headphones have a tendency to really bring out and make noticeable when a song isn't encoded well.
I hear they're more overrated than Bose. That is saying quite a bit.
I've heard that too, and then went out and bought a pair. They're not...