custom one pro is a cheaper dt770 which is easier to drive but not as good. the game one is based on the hd518/hd558 which is a cheaper hd598 based design.
if you want a neutral sound that is a bit more mellow sounding then the game one or buying a hd518/558/598 and adding a modmic would be good. essentially its similar to the game one but with a different color option and using a modmic not the included flip down mic. the hd518 is a bit more bassy than neutral the hd598 is a bit more neutral. the hd558 is between. the hd598 has the nicest pads, the 518 the thinnest pads, the hd558 a good balance in between.
if you want a more exciting sound (heavier bass and treble) along with overall brighter and more detailed treble the dt990 or...