Pros: accurate, very good imaging, portable, replaceable parts
Cons: comfort for others
The HD 25 series has been around for 15 years and this has been my 2nd purchase of the famed dual-band headphone.
Value: 10 years ago, if you are purchasing a $200 headphone it would've sounded absurd. Thanks to Beats by Dre, $200 headphones are now a steal. For $200, you get 2 pairs of ear pads (1) velour and (1) synthetic, also you get a nylon carrying bag, and of course the star of the show, the HD 25-1 II.
Audio Quality: HD25s are a favorite among DJs and broadcasters, although it is primarily designed for studio use, I rarely see this headphone used for mixing and remastering. The most common headphone, I see in studios are the ATH-M50 and SRH-840s.
Bass: It is there, present and just about right for a variety of tracks such as rock, hiphop, jazz, RnB, acoustic. But, if you are a basshead, this might not be for you. Bass is not deep as the ATH-M50s and the pacing is not as fast. This headphone will suffer from house music and dubstep.
Mids: Now this is HD25s cream, the mids are very revealing, it is an ENG headphone after all, it will be unforgiving on bad recorded tracks as you will hear all the pops on the vocals. This is great if you like absolute precision when mixing. And, those who love vocals will definitely enjoy this.
Highs: Average, rolled-off in some tunes, very common in studio headphones. Purposely done, not to fatigue your ears for long listening session.
Design and Comfort: HD25s are a ruggedly designed headphones, they are used almost everywhere by professionals. It is a favorite among DJs because of its isolation. This headphone can cancel out 20db of noise, better than those noise-cancelling headphones with batteries. Standing right into a noisy washing machine, I can't hear a thing with only 60% volume from an iPod, that's amazing. With isolation, you lose comfort. But in my case, I find this headphone very comfortable, the padding are well-balanced to distribute the clamping force of the band.
If you have a small ear, then it be uncomfortable. For medium and large ears, they'll be comfy since they will sit just on the inner side of the ear. Build quality is very good, plastics are tough, but not as polished as say Audio-Technicas. The plastics on the HD-25s are unpolished and raw. But, since I own this for 10 years, they are very reliable.
Split band will secure the headphone better, although, I'm not a fan of it. I use them as a single band. Also, there are a lot of aftermarket parts for this headphone, no worrying in breaking them. Replaceable ear cups, headband, cables with different flavors, ear pads and more.
Overall: The past 10 years, nothing has changed. But, this little headphone will continue to wow new enthusiasts and it will continue on production forever. If there is something to improve, it is to polish the plastic make it look more presentable and classy. Overall, it is still a highly recommended headphone, and it is my favorite DJ headphone for the clubs and commute.