I respect companies like Audeze and Hifiman which produce good products over the years and have developed from startup workshops to successful businesses as they are now. On the other hand I am appalled by Astell & Kern which is basically just iRiver disguised with an European name and keeps pushing out new products every two months with tiny improvements (yet charging $1K more every time).
AK380 is a complete joke. Standalone, it is barely better than AK240 and still cannot surpass Hugo in terms of SQ (but at a price much higher than AK240 or the Hugo). If you pair it up with the amp module, it basically becomes a desktop amp, or "transportable" amp. At the price of the AK380 plus the amp module, you can basically buy a decent desktop DAC in the 3K range, plus a very good desktop amp - from brands which actually have a reputation in making headphone amps - not iRiver. I respect people who make good headphones and headphone amps and actually put their research efforts into it much more than people who just put together different readily available DAC chips and wrap them with nicer and nicer aluminum bodies and sell them for ridiculous prices.
I am an AK240 owner but will probably never buy any of their products again.