We wholeheartedly recommend the DZ4 for whose sound preference is naturalness over technicalities, someone who wants a daily driver companion which can be used for hours everyday, not just short brief listening session.
Every once in a while in slow-moving industries like audio fidelity, there's a breakthrough in technology and there's a breakthrough in value. For the past couple of years we have seen multiple flavor-of-the-month chinese in-ear headphones aiming to take the top spot, but very few have stuck around. THe IKKO OH10 is a beautiful emergence from that competition, standing a class apart from the competition.
In conclusion, if you are in the market for planar (or for any headphone in most cases) in the $350 budget, this thing is an absolute beast. Pair this with a good pair of DAC+AMP and you are good to go for years
You get what you pay for; not with the Questyle M15, you get much more! If you don’t want to read further, let me make it short, you get top class desktop grade audio performance in DAC that fits on the palm of your hand.