Pros: Great for flat sound lovers, durable, multi-functional
Cons: Might sound boring to some, lacks driving power
All I can say is the X5 are for listeners who are purists to their music taste. They will demand everything is flat, so they can hear the characteristics of a mastering, but for average users, this might not be a great choice, and psychologically will make you feel that you have just wasted your money on something that dull. So, better be damm sure that flat music is what you are after, or not regrets might influence you.
At the meantime, I will stick to my Clip+ until the next big thing comes along.
detailed review : http://earfisensation.blogspot.com/2014/04/fiio-x5-review-flat-head.html