My experience is that I can adapt to the sound of pretty much any headphone over time, so that it sounds better over time. But what I look for is headphones that sound good to me in the first seconds, minutes, and hours, and over time they sound even better to me.
The headphones I currently have which sound really good me to all sounded good to me initially also. When I first tried the 99 Classics, I was immediately impressed with the sound, continued to be impressed with it when auditioning it at home for a week, so I decided that I had to keep it, even though I had several 'better' headphones which cost a lot more. Many months later, it sounds better to me than ever.
I recently tried the Z1R, didn't like it out of the gate, and that didn't improve after hours of listening over several days, so I returned it. I'm currently auditioning the LCD-4, and while it does sound quite good to me, I continue to like the sound of my LCD-3 and HD800S even more, so I won't be buying the LCD-4.