[Deltaechoe]

A lot of people dump on sennheisers because they tend to be more dark and natural sounding than many other headphones.  Bassheads tend to not like sennheisers as much because they a tighter, but much quieter bass response which can be increased with proper amplification but it will never be that INYOURFACEBASS that you hear from the basshead groups.  Another thing that I hear people say about sennheisers and I've found this myself is that they are picky headphones and easily expose flaws in the source hardware and recordings, this isn't the headphones fault but I do see a number of people take off points from sennheiser's high end cans (and other high end cans too) because of this.

 

[steve2151]

I find that Sennheiser generally makes a non-fatiguing headphone with great mids and a frequency balance that works for most genres. Their reference models are all very good.
 
The only thing I dislike about Sennheiser is their MSRP enforcement policy. I miss the days when the HD 600 and HD 650 were $250 and $330 street. At their current prices, they are usually more expensive than their AKG and Beyerdynamic equivalents.