This probably wouldn't effect me as much as it does, but the PX100-II's are one of my favorite headphones.
Appearance differences WITH the need of comparison:
1) Entire black appearance of the headphone is more sparkly on the genuine pair, while the fake has more of a semi-shiny black look.
2) "1" and "2" on the bottom sides of the arms are different fonts. The genuine has much more of a beveled look, while the fake is flat.
3) Font of "PX100-II" on the bottom outside of earcups is different. Genuine pair is thinner and cleaner, fake is thicker and a bit blurry.
4) The "garbage can and CE" on the inside of the left arm is much more beveled on the genuine pair. Similar to the 1 and 2 on the arms.
5) "L" and "R" are different fonts between both models. The genuine pair has a deeper engraved font, and the bumps on the L side are bigger.
6) Printed "Sennheiser" on the top of the headband is more of a grey color on the fake pair, and more of a black color on the genuine.
7) Headband is slightly wider on the fake pair, most notably due to the fake pair having a wider metal part. Slightest bronze tint on the fake pair.
8) Hinge joints on both arms are more of a dull bronze color on the fake pair, while sparkly silver on the genuine. They're also smaller on the genuine.
Appearance differences WITHOUT the need of comparison:
9) "PX100-II" lettering doesn't exist on the inside right arm of the genuine headphone, while the fake pair clearly has those markings.
10) The "S" logo on the outside arms is white on the fake pair and a sparkly silver on the genuine pair. Fake has blurry edges looking closely.
11) Cord is a 45 inches on fake and 49 on genuine, while being more flexible and feeling softer. Fake pair feels cheap and has many kinks in it.
12) Slight differences in jack colors, but the "S" has rounded edges on the genuine, and square edges on the fake. Genuine is also more beveled.
13) Taking off earpads and looking at the drivers, the genuine pair has numbers printed on the center on both sides, while the fake has nothing.
Build differences that SHOULD be apparent without comparison:
14) Earcup swivel is stiff and very restrictive on the fake, while easily maneuverable on the genuine. They also "click" into place on the genuine pair.
15) When folding the arms, the fake pair is very stiff and makes a loud "click", while the genuine is much smoother to unlock and lock.
16) Headband adjustment "scrapes" on the fake pair and doesn't stay in place well. Genuine has a definitive "click" with each increment.
17) A good rule of thumb; if you are getting the impression of unevenness or low quality in any of the moving parts, you most likely have a fake.
Unfortunately, I can't seem to find the box to my original, so I can't compare those. Also, bought them for $8.
Please see post #11 for great sound impression! Also, please see post #13 regarding comparison pictures.
Edited by Katun - 8/8/12 at 8:31am