I got my new Diana MR headphones from Abyss recently so I thought I should emerge from my hibernation cave again and post my impression.
First, if someone asks me to post a one-sentence summary about Diana MR, what should I say? Glad you asked.
Summary
If you want a pair of headphones that has huge out-of-your-head soundstage, high enough resolution for you to start hearing things you've not heard before in your music, smooth enough to be a daily driver that won't force you to abandon everything you're doing to listen to them, and have great bass, Diana MR is for you.
Impression (and a lot of comparison to other Abyss)
I'm an Abyss-for-life kinda person (I have the 1266 Phi TC, Diana TC which replaced my Diana Phi, and a recently departed Diana V2), so when Abyss announced that they were releasing the Diana MR, I naturally handed over my money to the folks in Buffalo, NY without worrying about listening to them first like a sane person would.
Luckily, Abyss does not disappoint. The carbon fiber version I got, which I hadn't even burned in properly yet, sounded good out of the box. Nay, great out of the box. Now let me describe to you what it sounds like going from one Abyss headphones to another.
From Diana V2 -> Diana MR
V2 is a super mellow and chill headphones that has great bass. I think V2 is always meant to be a forgiving pair of headphones that allowed you to enjoy your music at relatively low investment into your gears. Relative, because well, you know, V2 ain't cheap. It wouldn't break your bank to set up an audio chain that made V2 sound good.
What you get by going from V2 to MR is a similarly warm presentation of your music, HUGE soundstage that wraps more toward the back of your head, stronger bass, higher resolution that makes you appreciate your well mastered songs more. You'd lose a bit of that mellowness and chillness of V2 in exchange for something that sounded much more FUN. In terms of signature, MR is slightly more U-shaped than V2. In terms of the size of the soundstage, MR's comes pretty close to that of the big boy, 1266 Phi TC. In terms of investment, you're probably fine using the same gears you do to power V2.
On a side note, I got a loaner unit of Woo Audio Tube Mini to play with. It's a surprisingly good pairing with Diana MR. Diana TC sounds a bit anemic on the Tube Mini but Diana MR sounds great with it. I'd say that if you're traveling and still wanting to enjoy music in your hotel room, your phone, Tube Mini, and Diana MR would make a very convenient and good travel combination.
From MR -> Diana TC
Diana TC is not the kind of headphones that you put on when you are working, because you'll keep getting distracted by the voice of God in your ears, telling you to stop whaling on your keyboard and listen, dammit. You want to just lie down somewhere, close your eyes, and realize that every single penny you sacrifice at the altar of your audio chain is worth it.
That's what Diana TC is, something that demands that you invest your money into your DAC, amp, interconnect cable, USB cable, and even a power regenerator because you will hear every true upgrade you make. Diana TC scales insanely well. In exchange of you selling your kidney to afford everything, it gives you music that grabs your attention and won't let go.
Diana MR will sound better on better gears for sure, but not as drastically noticeable as Diana TC. Diana MR has bigger soundstage than Diana TC and its bass hits harder than Diana TC, but you'll get two things when you upgrade to TC: (a) incredible resolution and superb imaging that make instrument separation cleaner (although it would be less forgiving on your less stellarly recorded songs), and (b) more realistic representation of music with a more balanced curve than the slightly U-shaped Diana MR.
Diana MR is a much better daily driver than Diana TC because MR is more forgiving. TC is something you put on when you want to listen critically and just enjoy music and nothing else.
From Diana TC to 1266 Phi TC
Phi TC is even more merciless than Diana TC when it comes to exposing flaws. Diana TC is more mid-forward than Phi TC, it does not have the insanely high resolution that Phi TC does, and it does not hit as hard. Phi TC's soundstage is BIG and WIDE. Phi TC is not something you lie down and enjoy the music with. It's something you put on your head, stand, and jam along with the music. It's that engrossing. It just steals all your attention away. Phi TC is not highly recommended unless you have top-tier audio gears and REALLY well-mastered music.
Closing thought
I really like Diana MR. You should get a pair too. End of story