For a price-tag of $300, I think Dunu has hit a bit of a sweet-spot with the DK-2001. Essentially, what you are getting is somewhat of a “baby” DK-3001 Pro.
The M15 is a well-built device with top-of-the-line specs, multiple output options, and a bucket-load of power to drive pretty much any headphone out there
If you’re looking for a slightly warm signature which has just a bit of flavour added in the bass and treble, then you can't go wrong with the DK-3001 Pro.
Given the $60 price, the FH1s looks and feels like a well-designed product, but the sound signature leans heavily bright-neutral, and is bested by the EA3.