I have mixed feelings. For some genres of music, they are the best I have ever tried. Acoustic songs like "Hurt" by Johnny Cash sound truly wonderful. But anything else feels like going to a bass concert without actually getting the bass, and I'm always stuck on this line where you try to get something really enjoyable but it never quite reaches it.
They sound warm on their own, which can make them a bit dull in certain songs like "Down With the Sickness." But at the same time, they can produce enough treble when needed, and because of that, they provide a lot of detail. I've heard small details that were not present in other headphones or speakers.
For point of reference, I also have Cloud 2 and SHP9500. They objectively sound better and more alive than the Clouds, but they lose in several aspects compared to the Philips.
Confused? I am too. They have their good and bad sides. The reason I give them a 5 out of 5 is because objectively they are not bad headphones, and I struggle to find something better for this price.
There are the SHP9500, but I wouldn't say they are better. They are different. They have more soundstage, but because of that, they lose a bit in dynamics.
In short:
Bass: It exists, but it doesn't exist. The sound is permanently warm with boosted specific frequencies in the lows, but it doesn't have that thump, that kick that other headphones like the SHP9500 have (which are also open-back).
Mids: The results vary quite a bit depending on the song. In some rock and metal songs, they are a bit too boosted, making it sound a bit muffled. But in acoustic songs with violins and acoustic guitars, they are the best I have ever tried.
Highs: Overall, they are fine. Neither super wow nor bad.
At the end of the line, it depends on what you want. Those of you who prefer heavy disco or metal songs, I would suggest looking elsewhere. But for those who love acoustic songs and classical music, these are some of the best, if not the best, for their price.