Overall:
The ATH-M50 is a well built, beatiful HP. It has swivel earcups and comfortable high quality pleather pads. It comes in big white box with a leather bag and a 6,3 mm jack.
(ATH-M50 and ATH-M50S are the same HP. M50s has straight(S) cable, M50 has coiled.)

Sound:
The ATH-M50 sound great out of the box, but started to shine after ~50 hours of burn in.
They sound detailed, refined and balanced, with a strong but controlled bass.
The biggest quality of the M50s is, that they don't really do anything wrong. They performed pretty good with evrything I threw at them, and their sonic performance is outstanding in this price class.
I think it is hard to dislike them at all, but experienced audiophiles may find them to sound "clinical" or "booring", because they don't really shine at anything.
Newcomer audiophiles on the other hand will be blown away for sure.

The ATH-M50 made me realise, that a good HP is not all about sound quality.
A HP this expensive really has to fill all it's owners needs.
For me the isolation just didn't do it, and the pleather pads got my ears sweaty all the time.
But that's cause I used them as a portable HP mainly, which they were not designed to be.
Now with a high end portable HP (hd 25-1) I am as happy as i can be.

Conclusion:
The Audio Technica ATH-M50 is a excellent Headphone with outstanding sound quality in it's price class, but I would not recommend it as a portable HP.
Newcomers to audiophile equipment can't go wrong with this.

The other reviews for this product are not representative of the quality of this product. For more opinions/ reviews look at the ath-m50s review site

Overall:
The ATH-M50 is a well built, beatiful HP. It has swivel earcups and comfortable high quality pleather pads. It comes in big white box with a leather bag and a 6,3 mm jack.
(ATH-M50 and ATH-M50S are the same HP. M50s has straight(S) cable, M50 has coiled.

Sound:
The ATH-M50 sound great out of the box, but started to shine after ~50 hours of burn in.
They sound detailed, refined and balanced, with a strong but controlled bass.
The biggest quality of the M50s is, that they don't really do anything wrong. They performed pretty good with evrything I threw at them, and their sonic performance is outstanding in this price class.
I think it is hard to dislike them at all, but experienced audiophiles may find them to sound "clinical" or "booring", because they don't really shine at anything.
Newcomer audiophiles on the other hand will be blown away for sure.

The ATH-M50 made me realise, that a good HP is not all about sound quality.
A HP this expensive really has to fill all it's owners needs.
For me the isolation just didn't do it, and the pleather pads got my ears sweaty all the time.
But that's cause I used them as a portable HP mainly, which they were not designed to be.
Now with a high end portable HP (hd 25-1) I am as happy as i can be.

Conclusion:
The Audio Technica ATH-M50 is a excellent Headphone with outstanding sound quality in it's price class, but I would not recommend it as a portable HP.
Newcomers to audiophile equipment can't go wrong with this.

I bought the Sennheiser HD 25-1 (adidas) after my ATH-M50 had a loose connection and i had to return them.

Though I loved the M50's, they made me realize that a headphone is not all about sound quality.
Their isolation just didn't do it for me, and the pleather pads got my ears sweaty all the time.

The HD 25-1 finally does everything I need it to do.
The isolation is top notch, and the velour pads are more comfy then pleather while not getting sweaty.

Sound:
The sound quality of the HD 25-1 II was horrible out of the box, but they got better after a few minutes.
I didnt notice much of a burn-in process after that, and was quite disappointed with their sound, cause the only thing they did better then the M50 were drums and bass, while lacking a lot in highs, detail and especially soundstage and imaging.

After two weeks of frequent use and over-night burn-in (~200 h) they suddenly made a BIG leap in sound quality and especially detail and extension.
Compared to the M50 they sound more refined and detailed while also revealing a lot of bad recordings/ sources. the impact on drums and bass is just heavenly, like the overall bass response.

The only thing they lack compared to the m50 is imaging(not existant) and soundstage.
But since I use them as portable headphones mainly, that doesn't bug me at all.

Conclusion:
the hd 25-1 is a really decent hp and definitely one of the best portable headphones.
I especially love the user customizable style, cause i don't have to worry what might happen if my warranty were to run out.

If you find the pads to be uncomfortable, wash them in warm water. It makes them smoother and allows a better fit and comfort for the head.

EDIT: I bought the ADIDAS originals from razordogdeals.com, he gave me a 50$ discount, just shoot him an e-mail. Customer service was top notch, fast, friendly and competent.

I bought the Sennheiser HD 25-1 (adidas) after my ATH-M50 had a loose connection and i had to return them.

Though I loved the M50's, they made me realize that a headphone is not all about sound quality.
Their isolation just didn't do it for me, and the pleather pads got my ears sweaty all the time.

The HD 25-1 finally does everything I need it to do.
The isolation is top notch, and the velour pads are more comfy then pleather while not getting sweaty.

Sound:
The sound quality of the HD 25-1 II was horrible out of the box, but they got better after a few minutes.
I didnt notice much of a burn-in process after that, and was quite disappointed with their sound, cause the only thing they did better then the M50 were drums and bass, while lacking a lot in highs, detail and especially soundstage and imaging.

After two weeks of frequent use and over-night burn-in (~200 h) they suddenly made a BIG leap in sound quality and especially detail and extension.
Compared to the M50 they sound more refined and detailed while also revealing a lot of bad recordings/ sources. the impact on drums and bass is just heavenly, like the overall bass response.

The only thing they lack compared to the m50 is imaging(not existant) and soundstage.
But since I use them as portable headphones mainly, that doesn't bug me at all.

Conclusion:
the hd 25-1 is a really decent hp and definitely one of the best portable headphones.
I especially love the user customizable style, cause i don't have to worry what might happen if my warranty were to run out.

If you find the pads to be uncomfortable, wash them in warm water. It makes them smoother and allows a better fit and comfort for the head.