On audiosciencereview you can read that a price of a headphone has absolutely nothing to-do with how good or bad it will sound. There you will find many cheaper alternatives reviewed. You may want to wait for a review there.
QuoteAt the same time, the MM-520's low 18-ohm impedance means they're theoretically easy to drive, although there's more to that below.
I don't think this is how it works with planar, at least not as far as know from reading AudioScienceReview reviews.
If, in the meantime [until the ASR review], you want a 10 bucks cheap, but not bad with PEQ, alternative, check out: audiosciencereview.com/forum/index.php?threads/9-headphone-review-sony-mdr-zx110.19484/
Quoterelatively heavy
555g is indeed heavy.
QuoteExceptionally neutral frequency response curve, according to Audeze
This is not necessarily what the average ear wants. Instead they may want the Harman target curve. But I'm sure a PEQ can be applied (the price of a headphone does not mean that it doesn't need to be PEQ'ed, unless, of course, if the headphone is designed to fit a certain target curve; also, not every headphone can be corrected with PEQ). How such a PEQ would look like? Again, wait for a review on audiosciencereview.