Wasn't impressed by the packaging or the build quality, though it was cheap, I still expect Sennheiser to have some kind of standard. A lot more went into the nice fake leather case which fits many but the biggest of iPods very nicely.
The volume control is quite fluid in motion and won't move easily on accident, but both it and the Y-split are very cheap and plastic looking/feeling. Especially the clear plastic over the CX280 label.
But the reliefs on each earpiece is sturdy with a slight give and the gold-plated right-angle 3.5mm plug has survived many a knock and many a sit on.
The cable is a bit tangly, being rubberised, friction is quite high and the cable is microphonic at a decent touch.
Earpieces come in the standard single flanged three sizes.
Sound, though, is extremely suprising. The soundstage is amazingly broad and deep, something expected of maybe a 200ish dollar headphone/IEM. Quite V shaped in it's EQ, but they still sound better than $150 Shures.
Mid-bass is not boomy, (even a little lacking sometimes), but listening to John Mayer's: Where The Light Is, Steve Jordan's kit sounds amazing. The snare is tight and cracking, the kick is powerful and punchy and never bloated, the ride and the crash send tingles up my spine, Palladino's bass really drives the mix and Mayer's voice could be right there, live in front of you if you closed your eyes. It does get quite harsh if you really push the volume, but I love listening to classical and falling asleep with these on because it's so light, clear and airy that it doesn't seem like anything's actually inside my head and I don't have to worry about breaking them because they're so cheap!
These are really ideal if you listen to live recordings and want to experience to moment again.
Not so much pop/hip-hop, but you'll be amazed at the sound of Mtislav Rostropovich's Bach Cello Suite through these.
Sennheiser has really put a budget competitor out there to beat.
Burn-in takes a good 24-hours. Well worth the wait and the insanity freq sweeps bring.