This is the only DAC that I have owned at this point and I am currently looking to purchases something a little bit better in quality after buying a pair of Sennheiser HD 600.  For my liking the Fiio gets plenty loud and still sounds pretty darn decent but I have an itch to listen to tubes and to see if I can get more mileage out of my newest cans.  I'd recommend this little DAC product to anybody just getting introduced to headphones.  It's a well built product with enough features to keep one happy for a lengthy period of time and it offers the versatility to take it along on the road when traveling.  It even fits neatly inside the nice nylon utility pouches that came inside a couple of my hard headphone cases.  On top of all this, it doesn't cost an arm & a leg to get started in listening to music on headphones.

If you want more or less decent AMP and DAC for you headphones for under $100 or ever $80 you have quite few choices. Your options probably are SMSL SD793-II, SMSL M2 and Fiio E10k. Maybe few more. They are mostly the same. So somehow I ended up buying E10k, positioned as an upgrade for its quite successful predecessor E10. It came to me in order to replace Creative SoundBlaster E1.
 
Sound
 
Just like the competion Fiio's E10k sounds not bad for it's price point. Company's migration toward Texas Instruments hardware did it's job. I never heard original E10 but all reviews telling the same thing: E10k a huge step forward. While listening mainly to 16/44.1 instrumental music I had impression of some kind of stage, I heard decent separation and pretty sterile picture overall. Even though I listened for the same material I did with E1 the difference is titanic.
The problem is that some review pointing out that DAC in E10k is pretty good but what makes this device sound worse than it could is amp. After reading such thing I realized that device indeed sounds a bit dark and narrow. I can't call it bright by any mean. It's not that it's bad or something. It's just dark and sterile if you know what I mean.
Device drives my 80 Ohm headphones with half of volume in low gain mode, so I'm pretty sure you can drive 250 Ohms models with now problem, although manufacturer is recommending maximum headphones impedance equal to 150 Ohms.
 
Design
 
I couldn't find a single flaw. Device has a solid build with metal connectors and Japanese ALPS potentiometer as a volume knob. Beautiful blue led light near know indicates power and gorgeous brushed metal texture allover the surface makes this piece of hardware look a bit beyond its price.
 
Verdict
 
It's nothing special. It's just decently sounding product in rock solid housing. One of a few having amp and DAC under $100. It can drive your entry level Hi-Fi or studio headphones with no ******** and show you that somewhere over there starts a realm of her majesty sound quality.

for the price is good but if you want to have that premier sound qualtiy of studio you need a dac of 300 dolllar +