Why are these so cheap compared to other sites? And which would you recommend seeing as they're virtually the same price?
Sennheiser HD201 for only $20.13 at Amazon
Sennheiser HD 202 II for only $19.98 at Amazon
You are pretty much on the money for the best budget headphones.
I have listened to the HD201. For the price, it is quite amazing. If you have only listened to music via earbuds / logitech, you will be very impressed.
The most noticeable problem for 'cheap' headphones is that they are inefficient (very quiet), and don't have enough bass (the so called 'teeny' sound signature). They are also lacking in every other category, but you don't want to care about these other categories until you are willing to pay 3-figures for your sound. Some people like to upgrade to Beats, Bose or Skullcandy. I have dismissed these choices in an earlier post.
HD201 is very efficient, tt gets very loud very quickly. It has an amazing amount of bass, so much so that you'll feel like it's almost a nightclub in your head. It is relatively clear, has relatively good separation of instruments and vocals when the song is bass-lite, and generally much better than any buds that shipped with your phone/ipod and logitech. Heck, I'll even say it's much better than the $200 Beats.
The bad side is, it has a limited soundstage, the clarity of mid-range is not great during sections of prominent bass, the highs are not well represented (higher frequencies have lower volumes, i.e. a "roll-off"), and the sound is rather 'lifeless' (which is a subtle effect that comes from inaccurate reproduction of the recording). But hell, if you are going to listen to mp3s out of a phone/computer plug, it's not going to be that great. Anyhow, you will begin to improve on these factors when you upgrade to an external DAC/soundcard, listen to FLACs and buy a $300 headphone, and after that you realise you need to spend $1k to deal with even more problems, and possibly get an audio engineering degree.
The moral of the story is, HD201 is amazing for its price, and will be a huge improvement over other earbuds/logitech you've owned in the past.
Comparing HD201 with HD202ii is tricky, because they are very similar, everything becomes quite subjective. Some people have said HD201 is better at separation, but HD202ii has better bass and noise isolation. Some people say HD202ii are the most impressive headphones ever, other people claim they absolutely hate it. I've gathered that HD202ii does indeed have better bass, but HD201 has better vocals. In that sense, HD201 will also perform better with conventional instruments (such as strings). Both will suck at reproducing classical/indie/chill-out genres, this is to do with the dynamic range of the song vs the dynamic sensitivity of the driver. It works a bit like how contrast works, basically cheaper headphone drivers cannot produce (relatively) loud and (relatively) soft sounds at the same time. Both will be great at reproducing pop music like Lady Gaga, except the actual music will be anything but great. At least the bass will be loud.
My opinion is it's only $20, what is the big deal if one is slightly better than the other. Get the one that you think 'looks prettier'.
If you are willing to spend a bit more,
http://headphones.com.au/psingle?productID=444These are the most amazing under-100 headphones I've ever listened to.
You might want to ask JellyDonut about canalphones/IEMs in the similar price-range. They give much better audio reproduction than headphones at this price-range, because the drivers in IEMs are much smaller, thus they suffer much less from the dynamic range problem. However, you have to get used to the way they feel (one thing I cannot do).