Its other things you have to take into consideration aswell, not just sound.
On every other headsets I have used the quality of the connections have been very poor and gone even worse over time. For example, the XBL mic connection to the controller, the TB and the Sharkoons connections were constantly rustling and causing static and feedback. I found myself constantly re-connecting the mic jack and playing with it until the feedback went away.
I have used the A40's for nearly 12 months and they are as good as the day I got them, plenty of use out of them and haven't had one issue with any of the connections. So there is another reason for the price, the build quality alone puts them high above any other headset imo!