Disclaimer: My review may be rather invalid due to my lack of experience in the audio world. In that case, if you are new to this, it may be very helpful.
 
The HD 439 was definitely a good buy for its purpose of being my iPod's go to for music.
 
Sound Quality
The sound is great for the price. Very crisp at the mids to highs, and the bass wasn't overpowering.
The soundstage however, was a slight let down, being kinda too narrow to enjoy some more closed-off' sounding songs
 
Build Quality
The build quality is terrible, but expected for the price.
They are made of a cheap, lightweight plastic that does not feel durable at all (So little that I feel worried taking them in a bag due to possible breakage)
Comfort wise, these things are good. They are too light to be a burden, but maybe so much that moving around quickly may make them fall off.
 
Additionally, my ears (not that big) don't fit perfectly in the headset. This, along with the diagonal circum-aural earcup design means the headband feels like it is leaning forward.
 
Isolation
The isolation isn't very good. Even for closed back. Any comfortably loud volume that is enough to drown out other noises can be heard by anyone nearby, though not extremely clearly.
Think about that before buying.
 
Extras
If you have any lower quality mp3's, this will gladly identify them. The HD 439 make it very obvious when a low bitrate is apparent.
The replaceable cable (1.4 and 3 metres I think) are kinda tricky to remove at first, but not too difficult. The replaceable part is great if you break one though.
 
 
Summary - TLDR
If you are looking for a decent pair of headphones, that wont break the bank, are expendable and for use with a portable device (iPod for example), these are likely the ones to get. If you are looking for A+ quality in every field, you may want to look somewhere else. All in all these headphones do their job as a great set of cans to take places where you could break or lose them, due to them being rather cheap and still decent.
 
If you can afford better for at home use only, DON'T bother with these. Go look at some 558's or something.

First, a necessary disclaimer to tell you that I've never owned any other headsets or headphones prior to these. So my review is perfect for the newbies.
Additionally, I've owned these headphones for several months (I've lost count, but I bought them around September).
 
Pre-Setup
The Vengeance 2000 comes with
- The Headset
- Wireless Dongle
- Dongle Platform
- Charging cable
Getting the wireless dongle out of the box was tricky, and left me hoping I wouldn't break it, but that was about it.
 
Setup
Setup was a real pain, to say the least.
Firstly, you MUST have the headset FULLY charged before first operation. I don't remember why, but it caused problems for me when I didn't.
My computer must've blue screened about 8 times trying to get the drivers to work. I still don't remember what I did, but I know the computer crashes if you run the drivers
WITHOUT the usb dongle in. So remember that...
 
Build
It does feel solid, but definitely plastic. The headband makes me worried every time I stretch it, it's very rigid.
Design-wise, well you can look up pictures can't you?
 
Sound
Sound is amazing once you get the perfect EQ setting, which only took me 4 attempts. The fact that the sound is customisable probably makes this section redundant.
The 7.1 surround is terrible. It adds a very tinny sound over everything, and for position location, it makes it harder. 
Volume wise, this thing can almost deafen you at its highest. I find that I never have to pass the 30% mark, unless the song is quiet.
Sound is a definite yes, if you don't mind paying $150 for a stereo headset.
 
Battery
I had very high expectations for the battery life. Those were happily met with the results given.
The battery life lasts indeed hours, and only charges for about half that time. 
When the battery is running low it will sound a beep every few seconds. Which I'll admit scared the crap out of me the first time.
They can be charged and used at the same time though.
There isn't that much to say, except that battery life is great!
 
Comfort
Comfort is where this headset shines. It fits very snug over my head, though I only have each side extended 1 notch. The earpads are indeed more comfortable then any brandless headset you'll find.
Though if you've never worn full size headphones before, these will certainly take a little time to get used to, which at first meant taking them off every hour or so because they hurt my ears. Which 
by the way, happen to fit nicely inside it.
 
Microphone
The microphone is nothing special. It does its job well, but it's no studio grade large diaphragm condenser. Its noise cancellation I haven't thoroughly tested, but It seems to be working fine.
My friends could hear me very clearly over skype, no problems except for my unrelated network latency.
 
Summary
The Vengeance 2000 delivers very nice sound quality. But for that kind of price, simply being wireless stereo headphones is just not enough. I'm not picky about my sound THAT much, but the 7.1 is so unusable, I can't help but feel robbed a bit.
The wireless is handy, but it doesn't function properly outside my room. That 10 metres distance is halved if you go past a wall.
Charging is a bit of a nuisance, but doesn't deter from the quality of the headset.
It is extremely comfortable, and keeps my ears warm when it's cold.
To say the least, if you are new to headsets, this should be on your options list for research. Though I'd recommend you look at EVERYTHING in your price range.
If short distance wireless is an absolute necessity, these are a worthy option to consider.
 
But the $150 (AUD) price tag does seem a bit much for what you get.
Feel free to ask questions.
 
(Purchase date below is around the time I ordered)