Heyo cwa_asyraf
I've used both headphones(headset) beforehand, and I can surely tell you the M40X's will handily beat the Cloud II's in the sound department.
The M40X's isn't flawless in this scenario though. I highly suggest you to put some Brainwavez HM5 pads on since I find the stock pads to feel like "soft rocks". The new pads would also increase the soundstage.
If you however chose to go with the Cloud II's it would ONLY be because of the built-in microphone. Even it's virtual soundstage gets beaten by the M40X's WITH the pads mod.
Cheers