I have done a short A/B with XC & i found them quite good. XC has very balanced sound & is more organic sounding but TH 900 sound stage was better. XC has better mids , I liked TH 900 bass better. I have WA22 which very good mids hence it balances out TH 900 V shaped signature. My recommendation is if you listen to mostly rock music go for XC , If you listen to a good amount of EDM then TH 900 rules.
The TH 900 is more comfortable but XC is not uncomfortable, but I used them for a short while so please take this with a grain of salt.
The TH 900 gives more WOW effect than XC IMHO.
Edited by punit - 5/10/14 at 5:07am