I have the X4s and upgraded to the X41, then returned them and kept my X4s. There is a repeating "pop" when using the X41s I could not get used to and they just didn't sound as good imo. You can a get a "recertified" x4 from turtle beach as they don't make them any more for $99...
As I double checked, looks like they are sold out of X4s... you can get the X41 on amazon for $140 no tax and free shipping....