I own both the Miracle & HE-500 and, frankly, I love them..
equally. They'll work just fine for the genres you've listed. IMO, it's much less about technicalities at this price point (both are
incredibly proficient from a technical standpoint and will leave little, if anything, to be desired for most listeners.. their performance most definitely justifies their price).. and more about what sound suits your taste and other non-sound related factors (portability, isolation, etc.).
While they are deemed 'portable friendly' from an efficiency standpoint, I find a (robust) amp is absolutely
imperative to getting the type of sound you (pay for and) expect from the HE-500. They might get decently loud enough from an iPhone or DAP, but you're not even scratching the surface in regards to hearing what the HE-500 is (sonically) capable of. IME, getting a good amp to go with the HE-500 is
a must.
Being that they're open, fairly heavy, and come with a damn long cord, I don't consider them portable in any way, also. They're strictly 'home' phones... but what glorious sounding phones they are! If I had to describe their sound in one word? VIVID. Next to being in the studio or live in person, a properly amped HE-500 makes music sounds as real as I've ever heard.
The UM Miracle sounds fantastic from an iPhone or other above-average DAP. Though it truly shines when sourced & amped properly. They have a surprising amount of headroom and take advantage the power even very robust desktop rigs put out. I don't consider an amp/DAC a necessity for the Miracle in the way I do for the HE-500.. so while the Miracle will cost more than the HE-500, it doesn't require additional equipment to shine. It's also extremely portable to boot. The UM, despite being an IEM, has a jaw dropping soundstage & imaging (easily rivaling full sized headphones, IMO). It might have a larger soundstage than the HE-500, in fact.
Despite the HE-500 being an open phone, it's only (arguable) weakness is a less that (expectedly) wide soundstage that open, full sized phones usually provide. That being said, the HE-500 soundstage and imaging is still certainly top notch and very adequate.. for $700, I don't feel like I got cheated in that aspect of the sound, whatsoever. It isn't that the HE-500's soundstage is small or an flawed (not even close).. it's that
everything else is so incredibly marvelous... so if one is
forced to pick at something, it would (reluctantly) probably be the soundstage. Imaging remains top shelf.
Take into account where you plan to use your phones & how important portability & isolation are. The HE-500 are great, but if often listen to music on the go or can't have those around you bothered with music leaking from your phones, you'll get more pleasure (and use) out of the Miracle.
My answer on which to get? Both
/sorry about your wallet.