In same situation... I'm already have UE900 and XBA-H3, using them with FiiO X5, but now I need open-back headphone for home... I read in russian community that X1 will be a nice combo with X5. I have opportunity to buy it from amazon but no any chance listen to before buy... I also want to buy FiiO X1 as replacement to Sansa Clip for sport. MP4NATION gives good discount for FiiO Amp. when you buying something with FiiO Amp. Should I buy the E12 for X5+UE900, XBA-H3, Fidelio X1? Does the E12 add some weight for music? Will it be more warm, add punchy bass, increase soundstage?
Currently, I'm a little disappointed with X5 sound... For audiophile music it's a very good DAP, I like it, but for electronic music especially for experimental, industrial, Japan/Power Noise, sound is little harsh and tiny and for speedy bass music such as Mutant Break and Bass, French Dubstep, Drumstep, Breakcore etc, sound is little lack of sub buffer punchy bass. Anyway, I like the FiiO devices with same love as other people like the Apple devices and will replace my X5 only for the X7.
PS. Please, forgive me for my English