I had both and tested them for hours and hours and hours. There is very little difference. I ended up selling the mahogany because I intend to get the Ebonys when they come back to Massdrop next time.
X2. They are the same headphones, just the wood cup changed. It only changes the sound signature very slightly, hard to even discern the difference. This whole "gotta catch em all" thing is really stupid, only good if you want to spend your money for the same thing over and over again cause the cups look different.
There's so many other headphones you can buy and try with different sound signature rather than buying the same thing 2-3 times.
I'm only talking about the X00 variants. The TH900 are in a different class and sound very different.