i also compared two in a meet using akg k550, liked classic better so went with it. i think it pairs better with k550.
 
ot: does rx drive efficient full sized cans like k550 better than e12 or is it strictly for iems ?

@vaibhavp, yeah the I feel the Classic does better with the K550 but I rarely listen to them anymore.

OT: new Rx is pretty much for IEMs only. Ken tuned it specifically for use with IEM and limited the output power to 28mW. It's a purpose built amp that excels in that purpose.

Nice review. I just wish people would do more comparisons to something other than another Fiio player - half of the 30 reviews compare it to the first gen. X5, but there's like only one person who compared to to the DX90.
 
Not your fault by any means, but I was hoping someone would jump off the Fiio hype train and actually do comparisons to determine price/performance value (at least for SQ).

Fantastic Review!  Now I want one!  

Thanks @avitron142 and @BloodyPenguin

Just a note that the Review Details such as Audio Quality, Value, Design, Battery Life shown as green bars isn't what I've entered and no matter what I try to do to edit them they remain the same. 
 
I gave: 
 
Audio Quality 4.5 / 5
Battery Life 3.9 / 5
Design 4.5 / 5
User Interface 3 / 5
Value 5 / 5

Thank you for an excellent, detailed review!  I've been thinking about getting an X5 2nd Gen for a while now.  Your review has convinced me it will be worth it.     

Nicely done sir.

A great, informative review. I am tempted to get one through MassDrop.

Thanks @TraneTime, @Tuneslover, @reddog.

Thank you for the detailed review, Fiio's X3 ii & X5 ii feel like a pretty solid refresh!

I threw my hat in the ring and ordered it through Amazon.  Thanks again xRELICx!

I have an apple and a Fiio E12 ,I want to get a better Music player for under $300 and want to know if when hooking anything up to the main music driver the amp will overide it? I want something with an EQ that I can use on like say Bowers&Wilkins P7,PSB, or Hifiman 400,Beyerdynamic T-90? If you have some info ,please .

@Gram2 If you had some more detail it would help. You have an Apple what? iPod Classic, iPod Touch? MacBook? Essentially you can use a 30 pin to 3.5mm Line Out cable from an iPod Classic that would bypass the weak internal amp of the iPod to the e12 (you can't output from the iPod Classic to the X5ii). If you have an iPod touch you can only use the Headphone out to the e12 which would be double amping and not ideal (you can't use the iPod Touch to the X5ii).

If you have an Apple MacBook you can set the X5ii to USB DAC mode and connect your MacBook with a USB cable. This will allow you to play files from your MacBook and use any EQ or DSP available in the software you are using to playback music. The decoded digital signal is then sent to the X5ii for the onboard DAC to convert from digital to analogue and from there you can use the headphone output or use the Line Out to the e12 or another amplifier.

As a stand alone player the X5ii would sound much better than an Apple(?) but you need to figure out if it has a good synergy with the headphones you listed. If the X5ii power output is too weak for you then you can always use the Line Out function from the X5ii to the e12 to power more difficult to drive headphones.

I have been lookin at the first Fiio and maybe want to start with that. I have an Apple 4th Gen,touch with a fiio e12 that mostly powers my PSB MSU1,Bowers&Wilkins 7 and sometimes my other ones but I am looking for an IEM for under $100 ,I have Sennheiser 250 for IEM'S . My computer is the way of transfer with buur-brown . And I would like a better sound If I bought and tried out the X1 with the E12 and will the EQ overpower the DAC. The headphones I have are Beyerdynamics T-90,Hifiman HE-400,PSB M4U2,Bowers and wilkins P-7 and some low priced IEM's . I just want to know that the power will be good for any or most of these and will I have to use the seperate amp or will both conjoin together? Thank you!