I have the iCan on loan from Chico and while I want to get it back to him quickly I also want to try it out with gaming so I'll try to get some game time in while I have it. I'd hate to keep it from him for too long. I will say that I am digging that 3D switch for music and so far it's done an excellent job pushing the 650s.
No rush on getting it back. Really.
I won't be doing any heavy headphone listening for a while, plus I've got my M-stage anyways. So keep it as long as you like.
Make sure to play around with the 3D switch and sub-bass boost. They should work well on the HD650s.