For gaming purposes, which this is designed for, I cannot fault it.
Sound Quality - Great - It's also decent for music, but plays tunes at a noticeably worse quality than dedicated headphones, but nonetheless it is still above average.
Build Quality - Excellent - I love the material that the encases the wires, and for a gaming enthusiast with wires everywhere, it makes it easy to pick out which wires are your headphones'!
Comfort - Excellent - Yes, it's heavy, but after a month of use it becomes second nature. In fact, my old Sony headphones feel light and cheap now in comparison!
Microphone Quality - Excellent - There isn't too much to say here. It works, everyone else hears my perfectly.
Value - Great - It may just be that I'm a tightwad, but i don't really like to spend money to get more out of some games that I have already bought. However, I have had no trouble justifying the price, especially when you see higher-end sets costing upwards of 50 pounds.
Overall - Excellent - 5 Stars! I was stuck for choice as there were several headsets on Amazon for similar prices, but I in no way regret buying this one.