They can compete.
Sound is as good as the original, finish is good, but not as good as a 150 $ Beyer DT770 Pro fi. The Beyer will last 20 years, the 40 $ Superlux only ten. But that’s mostly the cable. You can get spare parts for the Beyer, but not as easily for the Superlux.
I’ve got a friend who is doing broadcast news sound in the field. He looses his headphones sometimes because they get sogged in the rain, doused in ketchup, or other mishaps. He wouldn’t even listen to the Superlux, so he kept spending his money on Beyers. One day, I slipped a Superlux in his kit. It took him several days before he noticed. And he noticed because the cable was more flexible. He never bought another Beyer again. He looses Superluxes these days…
Superlux used to make Sound Devices clones (only portable mixers and headphone amps, nothing digital). Sound Devices is really good gear, but pricey as hell. They were as good as the original, only less than 20% of the price. Under pressure from the original manufacturer, they stopped making those. Now they make their own gear which no longer looks like something else. Because of the history of the brand, some American shops still do not carry the brand.
I have Sennheiser HD380’s. These are fine too, but I think they are a bit too expensive at 199 €, as the 30 € Senn HD201 is almost as good.
Anyhow, headphones are even more personal than speakers. You will be wearing them. Try to listen in a shop that still offers that kind of service. And if you are a kind person, you might even buy them in a shop that offers that kind of service. Can’t listen to them on Amazon! It may not tell you a lot about how they sound (as the gear and material driving them might be awful), but you can at least feel how they fit your head.
An important question is also: closed or open?
If it’s for voice-over or other “pro” applications, you probably want closed.
http://www.thomann.de/be/superlux_hd660.htm
If it’s for listening to music in a quiet environment, you 'll want open or half open headphones.
http://www.thomann.de/be/superlux_hd681.htm
http://www.thomann.de/be/superlux_hd668_b.htm
My Senn HD380’s sound good, but the covers on the earpieces murmur a little, unless you keep your head fairly motionless. So I have a number of HD201’s that get far more use. They are quiet, cheap to replace and sound good too.
I also have a pair of vintage AT condenser (electrostatic) headphones. These are 40 years old and require at least 50 Watts per channel to drive them. When it comes to detail, they still outclass the Sennheisers. But with only 2m cord, a heavy transformer case and a stereo amp next to them, they aren’t very practical. A headphone needs to be practical, light and comfortable to wear. And these are not. The earpieces ride on top of my ears, for instance. The headband is too loose. I would never buy these again. And certainly not for the crazy price from 40 years ago. But when it comes to finding sore spots in recordings, they are my personal weapon of choice.
There are lots of other good headphones, from Beyer, Shure, Audio-Technica, AKG…
