Let me copy paste a fellow headfier that just bought a Panasonic HTF600-S. A Ultrasone Pro900 owner to be exact.

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- offline
- 60 Posts. Joined 2/2010
- Location: San Jose, CA
I've convinced 4-5 of my close friends to get these headphones.
I made each of them guess the price after listening to the Panasonic's. 
All of them guessed significantly higher! $100? $150? $160? NOPE!
And to their surpise when they found out they only cost $30... Total shock and awe!
Sadly, the price has jumped to around $40 including shipping fees.
EDIT:
My cousin sat down and compared the Panasonic RP-HTF600-S to my Ultrasone Pro 900.
He definitely had the WTF?! facial expression on! Comparing the prices between the two headphones, he told me to sell the Pro 900s ASAP...
MalVeauX is not kidding about these and I am neither.. You should try one.. I have the DJ1s. Let me just say. I listen to these way more now a days.
Oh wait I have another one for you. A Pro beats owner that just bought one.

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So I've had my htf-600's for a few days now.
WARNING! - First review
Originally, I purchased the Beats by Dre Pro headphones (steep discount from employee). Needless to say, the Beats Pro have really thumping bass. However, the mids in the Pros felt lacking, and when turned up (un amped) I feel like the Pros have some distortion to them.
In comparison, my 600's felt a little dull at first. Nice sound stage, and great quality. After a few hours of usage, the bass came out to talk for a bit (so to speak). I then threw my Fiio E6 amp on them....Holy Hell.
It's like listening to 2 different headphones. The bass hits hard (shakes the cans) and it's very satisfying (fun sound). Sound quality (imo) is better than the Pro's. Thanks for getting me to notice these! Great deal for quality headphones.
My one gripe, is sound leakage! The Pro's could be cranked up 100% and no one within a foot of me would hear them, however these 600's seem to be heard across a room at ~60-75% volume. Would anyone suggest changing these pads to the M50 pads? Would that help any with the seal? Is it more comfortable?
Edited by Dsnuts - 10/5/11 at 12:42pm