I have had many sub-$100 headphones from $5 Panasonic to $100 Sony, with Sennheiser HD 433, 202, PX100 II (I really wanted to like these PX100-II, they were so very well designed), and even a Grado SR60 for awhile.  And what it basically comes down to is value.  I have never heard sound as good as these headphones in the $35 range, easily the best under $75.  I can't believe they're over 25 years old.It's hard to describe how much detail these headphones bring out without making it too harsh or dull.  I listen to every type of music from classical to hip hop to electronic to country, and these headphones are suitable for all types of music.  The only fault in the sound is the bass.  It's just a *slight* bit boomy, but you get to like it after a while to be honest.The design is from the 80s as you all have probably figured out.  It could use a update but it seems like Koss has tried to perfect this formula and failed in the past.  I don't really care about the looks or the way it folds up or the fact that my hair gets caught up in it (I have very short hair, even for a male).But despite it's design flaws, it's the most comfortable headphones I have ever worn, and the best part is that it's also the best sounding pair of headphones I have ever heard under $75.If you can get over the design flaws or if sound is the most important feature of headphones for you, there is nothing even close to this at this price range.This one is an absolute GEM.  I loved these so much I ordered two of the 25th Anniversary ones for a bit more.Update: I read some reviews about the PX100-II being much improved and better sounding than the PortaPro.  Since the PX100-II is relatively new, I thought I'd give it another listen.  This time I noticed something different.  The sound is warm, mellow, and neutral, but it loses a lot of detail at the expense of these attributes.  I still prefer higher-detail Portapro, but some may prefer the more mellow sound of the PX100-II.Oh by the way the Portapro comes in the straight plug now, not the angled plug anymore.  It's supposed to be for better compatibility with the iPods and iPhones out there. 

Question: How is the bass?
Answer: The only fault in the sound is the bass