After few month of use I can say it's Okay-ish product but not best. You would need a additional amps in order to get more bass and clear sound.
Oppo Find 5 mobile phone has more better sound than Fiio X3 II. I will give it 3 out of 5.

Best music player I've ever heard by a long shot. The amplifier in this machine blows away any iPod. Sturdy design. Love the rubber protective cover it come in. Plays most files including FLAC! And the price is amazing.