Logitech G930 are great ones.Excellent sound quality and amazing comfort.
Anyway,you should know that a friend of mine upgraded to Razer Kraken 7.1.
He got them and they were faulty.He RMAd them and got another 7.1s.
They were faulty too.
He ended up getting the Logitech G430 and he hasn't had a problem.
I should also mention that when getting Razer headsets,you're paying for the headsets themselves,but not quality.At least that's what I heard.