I've had these now for about 2 weeks now. I got these for a good price on ebay, they were open box, meaning the box was all beat up but the headphones were fine and in new condition, it's a win-win! I'm not as experienced as some members on here so if you'd like, take my review with a grain of salt. I also won't go into much depth as some reviewers do. My sources are Laptop>FiiO E10 and an ipod nano 5th generation. All music i listen to is mostly 320kbps with a few flacs and ogg vorbis. I also like to listen to my music at moderate to high levels, mostly electronic, synth/pop and some odds and ends like rock, rap and classic.
 
Comfort and Build Quality: 7/10 
When i first got them i was surprised on how comfy they looked and feeled, very squishy ear pads. I was also surprised how much they weigh. After a few days, the cons in comfort started to show. I can only wear these for about 90 minutes and then i have to take a break. First, my ears started to touch the drivers, the ear pads have flattened out slightly, but even before that, my ears were touching them. I even removed the foam that covers the drivers to get more depth for my ears, that only worked for a day or two and my ears started to touch again. I'm also not a fan of leather ear pads, but that's personal preference. I'm in the process of ordering some thicker velour ears pads. The other issue with comfort is that these things are heavy, especially with the coiled cable attached. They feel about twice as heavy as my HD 558's when they're on my head, hell, even when i'm holding them in my hands they feel that heavy. I don't have a accurate small scale so i can't give you facts. So that's comfort, i would give my HD 558's a 9.5/10 for comfort, so there's a comparison if you already have some comfy sennheisers. But then again, maybe your ears don't stick out as much as mine and you like heavy headphones with leather earpads, you'll love the comfort then. The build quality kinda ties into that stuff i mentioned, but other then that, this headphone is well built and will probably last me many years, as long as i don't toss them out of an airplane. 
 
Sound: 9/10
For the price of these, they are really good. I did notice some burn-in changes, whether it be from the drivers or my brain getting use to the sound, i don't know, all i know is that there was some slight changes. The sucked out lower mids some people talk about, i did hear in some songs. After a few days though, the sucked out lower mids seemed to disappear. That or i just got use to the sound signature. I switched back to my other headphones though and i couldn't pick it up, where as at first, i could. The bass might have gained a little power with burn in, the mids didn't change, the highs did get a little more clear.
 
***The sound stage, imaging and separation is decent compared to my HD 558s (558's being the best in the category) and is great compared to my MS-1's... lol, I don't really know what is good for a closed back headphone so i won't really touch on this. Although the sound stage and imaging is almost comparable to my modded 558's, it's more of the sound separation that's a little lacking. This could be an illusion, maybe from the resonating sounds coming back from the ear cups makes it cluttery at high volumes sometimes, i'm not sure, i'm not really the best person to ask about the sound stage and separation, i have a hard time picking up on it, probably because the music i listen to isn't full of dynamics like classical and jazz.
 
Sound isolation is good on these. They leak almost no sound at moderate levels, they will leak a little a high volume though. Although they do leak sound in a little bit. So if you're walking down the road with these on, you will definitely hear a car horn, i'm not sure if that's a good thing or a bad thing -_- lol.. for example, most IEM will give you better sound cancellation. I don't know the specifics, but if i would have to guess, they cut down around 60% of the sound around you. Does that make sense? arghh, moving on..
 
Bass: The bass is pretty good and extends very low. It is a strange phenomenon, the songs that were made with bass in mind, have bass, while the songs that focus more on the midrange and highs, don't really have any bass. I almost always have bass boost switched on with my E10, and it does make a world of a difference. That's with just a $60 amp, who knows what other amps are capable of doing to these You can also EQ the lower frequency quite well with these. If i had to describe it, the bass is more thump and less kick and peppy. It's boomy, but not a sloppy mess, it's accurate, but not too accurate. It's like the bass is more focused on the lower bass frequency (80hz-120hz), the mid and high bass isn't as strong (150hz-500hz), maybe this is the mid bass/low mid suckout? I'm not sure, but it's hardly noticeable, some people were blowing it way out of proportion in my opinion.
 
Midrange: Very good midrange like my 558's, not much to say here, they're not laid back nor forward.. although for my tastes i think they're a little harsh, nothing the EQ won't handle though.
 
Treble: Not much to say here either, pretty flat frequency response. The vocals are not too forward or laid back, i would personally like them to be a little more forward, but that could be my amp and EQ settings too. Oh, when i removed the foam that covers the drivers, the treble did brighten up a little bit, just how i like it. The treble is never harsh or fatiguing. It has really good extension for a closed headphone, i can hear all the way up to 16khz. Nothing really drops off anywhere. 
 
Also, the speed/attack of these headphones (is that a thing?) is moderate. They're not laid back, nor too fun, they're balanced in this regard. Which is great because fun headphones do get fatiguing after a while and laid back gets boring after a while, for me anyways.
 
Overall, the sound is really good and flat. I had a hard time EQ the sound because it's already pretty much perfect (for me), most of the time i just left the EQ on flat. The midrange can get a little "in your face" and fatiguing i found. So now i have a very slight v-shaped EQ in winamp, it suits my preference better. Everybody is different though.
 
I like what some other reviewer wrote a while back. Something along the line of "For the $200 price tag, it's a great all rounder, there are better alternatives for specific genres of music, but the HP100's does pretty much everything well." It's a jack-of-all-trades kinda headphone, although i also think this jack-of-all-trades is also an expert in a few genres like electronic, rock and rap/hip-hop. 
 
I know my average makes the rating 4/5 stars, but i'm going to give these a 4.5/5 stars because most people think these headphones are really comfortable, i must be the odd ball out or something. Plus lets be honest, it's all about the sound, amirite? The sound these produce for $200 is really good. I'm still a little confused about the frequency response chart, i can't find any frequency response graphs on headroom or golden ears. I don't hear the dip in the midrange except for the mid-high bass a little. I actually tried to EQ it flat (looking at the frequency response on the box and then doing the opposite) and it sounded horrible. I think there's some sort of illusion soundmagic is pulling with these, the frequency response is outta wack but the perceived response is actually quite flat with a little emphasis on the lower bass. 
 
Anyways, this is my first review on here, if i missed something or if something doesn't make sense, feel free to let me know! I wanted to write this before a start doing anymore mods to these (currently just the foam removed). I'm getting new ear pads to see if that helps with the comfort factor. I also might try some damping in the back of the ear cup. I don't modify because i'm not happy with the sound, it's just the potential is all, there might be potential, every headphone can be improved with some mods, in my opinion.