Pros Treat audio very evenly. Jazz, classical sound as good as one could want on these. If you prefer rap, pop, dance, these will struggle to deliver the lower end you desire---even muddle it somewhat. Extremely comfortable--could wear all day and not tire.
Cons S:N ratio is not the highest, so they are not the most efficient phones I've used. They are not for the plane. Open air style doesn't cut out external noises at all. Also that means if someone else is in the room and you're jammin' out, it may bug them
Summary I love them and use them often, but I have a another set for rock n roll that is more closed.
Pros Frequency range, Clean highs, Great bass response, Build quality, Very comfortable, Single cord design.
Cons [Nit-Pick ALERT] Cheesy storage pouch.
Summary I went to Best Buy last month and sampled several headphones to go with my Archos 5 IMT because I wanted a good wired headset. I normally use Bluetooth Stereo. After 30 minutes of test-tuning various models I settled on the HD238s.
These headphones sound awesome! They have a broad frequency range and reproduce clean and clear highs. Some have knocked them for not having good bass but those folks must be hard to please. The bass from my set sounds great and have been able to handle any song I put through them..., playing clean and accurate lows. Lossless audio really helps these units shine.
These units are also very comfortable with their thick padding on the speakers and on the top bridge. Their articulated design let's them adjust to virtually anyone's head. The build quality seems high too, with metallic components here and there. They are lightweight considering their size, and have good formfactor especially with their anti-tangle single cord design, and you can also swap out the ear pads if they get dirty.
The 2 year warranty is also an awesome plus. I like a company that stands by their product.
Pros Great accurate sound, comfortable fabric/leatherette over foam earcups.
Cons Over the head style like full sized headphones, so they're not made for running
Summary After wearing out the foam earcups on my last Sennheisers I was looking for a non-foam option. These fit the bill. They are not the cheapest Sennheisers that are made for portables but they are the best sounding and have a nice fabric and leatherette earcup that won't wear out like foam.
They accurately reproduce music at any EQ setting (unlike larger Sennheisers that need to have the bass turned down). The earcups turn down to create a flat profile for easy packing and come with a carrying bag.
Pros Crisp clean sound. Emphasizes on treble. Lightweight and comfortable to wear. Cheaper alternative to similar on-ear headphones.
Cons Lacking in bass power. Feel almost fragile. Comes with cheap bag. Should feel like $100 worth on more than sound quality.
Some might not like "open air" style that makes it easy to hear ambiance.
Summary For around $100, these headphones both look cool and deliver high quality sound at the cost of bass and possible durability of the headphones themselves. Hearing surrounding noise is usually not an issue because of the rich sound produced from the headphones, plus the lightweight makes it feel like its right in your head.
Overall, great headphones.