This is just a quick comparison of both, for anyone who is looking for some good overall budget minded cans.
***Panasonic HTF-600 vs Superlux 681(red pair)***
Both sets generally receive good to excellent reviews(Especially in the bass department) from owners and can be had for under 30 dollars if your willing to shop around. I mainly listen to "chillstep" and acoustic genres. I also didn't want to break the bank, so both of sets fit my criteria.
LOOKS: I won't say much for aesthetic appeal since you can easily see many definitive pictures of both on Google images. Personally, I would give an edge to the superlux's, although the panasonic's aren't lagging too far behind.
Lux: B+ Pan's: B-
COMFORT: Both are full sized circumaural headphones and both are comfortable enough for extended periods of listening. The Super's have a circular pad which fits nicely over the ear but the Pan's ellipsoid shape does a slightly better job covering my ears. Pressure on the head is about the same. Everyone's ears are different but for me I give a slight edge back to the Panasonic's on overall feel and comfort.
Lux: B Pan's: B+
SOUND: Once again this is a nutshell review, so i'll spare the details. Both sets lived up to the hype. The unamped bass response on either pair was above pair without compromising overall sound quality. The bass on the Panasonic's was a very punchy, where as, the Superlux's bass was a bit more on the fat side. As for clarity, I think this is were the Superlux's finally pull away. The Panasonic's have great bass and are good enough in the high/mids category, but in comparison sounded a little muddy to my ears. As for the 681's many people complain about the overemphasized highs and subdued mids, but I have to disagree. Whether, i'm listening to dubstep or acoustics, they always seems to reward me in clarity and bass response. The FTH-600's are excellent sounding headphones that more than get the job done, but the 681's turn listening to music into a religious experience.
Lows A+ A
Mids B- B
Highs A B
PRICE: Both sets are equally priced and both are equally a great bargain. The rest is purely subjective.
Lux: A+ Pans: A+
Hope the is helpful to someone.