I've actually owned beats before, true story.
Before I even knew they were hated (not trying to play the hipster card, I promise), I had bought Beats Studio because at the time, they were the only wow headphones being sold at my Best Buy (and I didn't buy stuff online back in the day). I spent a good amount of time with them, and then one day my buddy had his ATH-M50's with him. And when I compared them side by side, I preferred the M50's. And while I then went on a long journey of trying out almost all the big name brands (Sennheiser, Grado, Audeze, Denon, HiFiMan,AKG), I still managed to give Beats another chance with the Beats Pro in 2010.
And I honestly did not think they sounded that great. Are they as awful as some say? No. They didn't sound terrible at all. But they were never IMO well built or did sound incredibly well. They certainly never justified the price. Well, the Pros are actually built like a tank (I was talking more about the cheap Studio headphones, that feel like plastic). But the Pro feels like you are wearing a hunk of metal on your head, and I never liked their design.
I by no means consider myself an audiophile. If there is such a term, I guess I'm a casual audiophile. In that, I do care about quality. But I also don't take this hobby as seriously or passionately as most of you. So I can only speak for myself and my ears, but I always found Beats to be a very subpar product.
It's not as bad as some say. But I get the annoyance. You have a headphone that isn't special, and it's the most sold and advertised product on the market (and sold at a higher price based on this idea of excellence). But then again, I would compare beats to Mainstream pop. The demographic really isn't aimed at you. So why get upset? Does anyone here think the average music listener is going to find appeal in the HD-800 or LCD2 (even if they were much cheaper)? The only way to sell to a mass market, is to give a watered down product. It's why two and half men is one of the most watched shows on TV. It's inoffensive, and has a wide appeal. Compare that to a more clever/niche comedy, and suddenly you turn off a lot of viewers. Similarly, Beats have come up with a design (aesthetic appeal), and marketing that just really appeals to a lot of people.