Selection Guide

From all the positive reviews I've read so far I had the impression that it's impossible not to love these headphones, but unfortunately they don't suit my taste at all.

Unequalized, the sound is bright, thin, and sharp. For example, when Diana Krall sings 'In other words' in Fly Me To The Moon, the 's' feels like a cut with a scalpel right through my eardrums.

Only after the reducing the dominant treble a lot, the HD668B stopped to seriously strain my ears, but it still had an overall thin and sterile signature that I couldn't really find enjoyable with any kind of music.

I'm not implying that everyone will feel this way about the HD668B because obviously many people really like it. I'm probably very sensitive to pronounced treble and people who are as well should look for something else.

What I really liked was the fact that the cable is exchangeable and both a short and long cable are included.

The build quality seems to be adequate for the low price and the comfort is OK although these headphones do not have ear adjustments.

Just a little back story. The TL;DR will be afterwards.

These are my first "serious" headphones (I know these aren't suppose to be amazing headphones, but to me, they sound AMAZING!)
I'm an avid music listener through school, and on the bus, and have been using ear buds for years (mostly the $10 Skullcadys, which in my opinion are pretty damn good, but switched to the Sennheiser CX200's), and for some reason just felt that I should get some headphones.
Now I at least wanted to spend $50 because I wanted quality, but didn't want to spend too much. I was recommended this site from Gamespot.com, and decided to look around based off my price range, and by best reviews, and these had a very a good review from this site, and all 5 stars from 3 users, not to mention being at my kind of price, so I decided to order them.
Now I was not sure how well these were going to be because I could only base my experience off ear buds, but I did expect these to at least sound as good as my CX 200's, and cancel out sound better. Now again, these sound AMAZING based off my experience, so I can't compare these to any other headphones (I might go back and try out the stupid Beats to see how they compare), but they sound better than my ear buds, and they seem to cancel out sound a bit better. I also love the detachable cord so I don't need to wrap the cord around the headphones, but I'm stuck between a cord that's a bit too short, and a bit too long for me...
Now the main reason I didn't give it 5 stars is because of how much these things leak the music (which is strange because no one seemed to mention it, unless they're suppose to?), and I don't want to be the guy that disrupts the people around me. I have the volume up loud (which has to be like 70%-80% volume) enough to where the music sounds perfect, and can barely hear my surroundings, but when I recorded myself having them on, they sounded like they were partially projecting the sound out of the headphones (which I'm thinking the sections of tiny holes on the outside of the phones are doing?). But if you don't care about people hearing your music, then these are definitely right for the price! Sadly for me, these will have to stick to home-use...

TL;DR
Sound- The music is very clear. You can hear every instrument, every detail, and the base is pretty strong (but not as profound as the Beats phones)
Comfort- I haven't had them on for hours, but having them on for about 30min-hour, they never got uncomfortable, but like other over-ear phones, your ears will get hot.
Look & Feel- To me, they look very nice/professional.
Durability- I don't plan on dropping or throwing these things around, but they seem like they would be able to handle it.

Bottom Line- If you have a reasonable budget, love music, and don't care about other people around you hearing it, then these are PERFECT for you! I'm happy to have started out so strong. This may be the beginning my headphone "career" lol.

(First off, I'm not a high-end audiophile by far, and I'm not an analytical reviewer.)

SOUND:
Believe the hype these headphones have generated. These are the best (neutral) headphones -- when you consider the price vs. sound quality ratio. Of course these aren't really the "giant can killers" that everybody claims they are, but they are damn close.

That said, these cans are really, really hard to beat given their price to performance ratio. They are so neutral that I was blown away when I tried them out for the first time. Like the reviews before me, I thought to myself "these cost how much?". I tried orchestral tracks from Two Steps From Hell, alternative bits from Hootie and the Blowfish and Great Big Sea, some mixed rock from AC/DC and GnR, tried punk with Bad Religion and Social Distortion, and finally some good old classic rock a la CCR. These 668B's handled everything I threw at them with aplomb.

Perhaps their neutrality was even more evident to me as I was coming from Sennheisers (202-I, 228) and Grado SR60's, with both companies being quite well known for having their own sound signatures. Neither signature is neutral, however, and that must have been what amplified my "wow" factor to these neutral heaphones. Paired with my Fiio E5 and Cowon S9, I've previously setup multiple EQ profiles to deal with the "fun" sound signatures that Sennheiser and Grado have. With these Superlux's, I have literally turned off the EQ (but had to turn up the volume a bit).

BUILD:
The build quality leaves much to be desired after coming from Sennheiser and Grado cans - both companies really build great products. Superlux calls themselves an OEM manufacturer, and I believe every letter of it. I'm not afraid of breaking these cans from daily use, but I do feel like they may break if too much outward pressure is applied to the headband. The earpads are also of a cheaper pleather than I would have liked, and they feel a bit stiff compared to other pleather earpads I've had experience with. This stiffness creates a bit of extra work to get a good seal around the ear - perhaps they will soften up over time. I intend on getting AKG velour pads down the line, so I'm not overly concerned about the current pleather earpads.

The two detachable cables, 1M and 3M, are very convenient for mix and matching. A bit like Goldilocks, but I do wish that it came with a 2M cable, as the 1M is a tad too short for my use, and the 3M is too long. The clip that holds the cable to the headphones is very convenient. I wish that Superlux would ship out more than just 1 unit though, as it seems like it may be quite easy to lose them.

CONCLUSION:
Again, I must say that you can easily believe the hype behind these cans when you realise how they sound at $50. These are not "the best headphones in the world. Full stop.", rather these are the best headphones for this price. They could use better earpads for overall fit and comfort, but so could many other headphones that cost more than these do.