First of all, I received the Edition XS on 31st March 2022, and I was impressed by it on the very first day itself. However, I took time until today not to get carried away by the initial enthusiasm and give a fair review of these headphones. This review will be divided into various sections.

My audiophile setup: Hifiman Edition XS running balanced from Xduoo XA10 (dual AK4493 class A 4w@32ohm Dac/Amp)
My Listening sources: Tidal, Qobuz, native mp3 files and YouTube

Build: There is no getting around it. Hifiman Sundara has better build quality than the XS due to the use of more metal in the construction. Sundara also feels more solid in the hand while weighing less. However, Edition XS has still good build quality for non-portable open-back headphones.

Comfort: This is a more subjective area. The Edition XS is very comfortable, far surpassing the Sundara. The earcups are much more spacious than the Sundara, and they also distribute weight more evenly. The headband also does not cause any pressure points on top of the head. However, YMMV

Sound: This section is the reason why I titled this review as "The Grand Sundara!". Imagine the sound signature of Hifiman Sundara but more open, grander in scale and with better bass punch and overall dynamics. You get an idea of the sound signature of the Edition XS. An interesting contrast from the Sundara, which I have noticed, is that this headphone has more vocal intimacy than the Sundara. At the same time, the sound stage, in general, is wider and larger in scale than the Sundara. This leads to a more enjoyable and slightly better-layered presentation of the sound than the Sundara. Here are some reference soundtracks and what to look for in each.

1)We’ve Just Begun-Sinne Beg: Soundstage, vocal forwardness, Layering

2)Naatu Naatu-RRR: Punch and Dynamics, fast-paced dance music

3)Komuram Bheemudo-RRR: Male vocals, ballad-like tonality and theme

4)Come away with me-Norah Jones: Female Vocals, melody

5)Liar-Sandra: Flute in the beginning portion, female vocals

6)Whiskey River-Willie Nelson: Male Vocals, busy instrumentation

7)Your Love (Extended Version)-Kate Linn: Sub-bass at the beginning

8) Straight Out the Gate-Tech N9ne: Hip hop, fast-paced music

An excellent headphone with a very wide sound stage. the clarity is exceptional.

It would have been 5 stars if not for two main issues:

1. Slightly sibilant. can be managed with a slight bass boost but its noticeable
2. very weak headband grip. i understand its meant to be light and easy on the head but it feels like its going to fall off if i move my head.

Overall a very good set of headphones that make my HD650 feel like closed backs.

I'd like to begin by saying this is my first purchase into the High end/Enthusiast headphone segment. These headphones were bought for-

1) Casual listening on a smartphone, and
2) Gaming on a Desktop using DAC/AMP and a mod mic attachment.

So far, I have made do with a pair of Audio Technica M50Xs for both (without an AMP) , which for the last 6-and-half years had served as a reliable and robust daily driver. They have had 4 ear cushion changes and one headband change so far, but after one of the drivers finally gave in, the headphones started sounding unacceptably muddy at the lower end--It was finally time to put these to rest in the hall of fame.. (Right beside my now deceased logitech g503 and other *upto 10 year old random gear, that I still hold onto for a nostalgia factor! I guess I'm a romantic that way :)

That also meant it was now time to start looking for a worthy successor. Yes, there are some pretty high end gaming headphones out there(even in this price bracket) and yes, the sensible thing to have done was to simply get a razer blackshark V2 Pro or even another m50x really, since I am pretty comfortable and familiar with the sound signatures on both. This time though, I decided to venture out of the "hamburger with cheesy fries and a large coke" order and into the "steak with a glass of red wine" listing, and even though I knew that 35k couldn't really get me Wagyu steak or a glass of Bourdeoux, I knew what I'd be getting would still be a considerable step up from the Hamburger!

So upon discovering that I have probably recieved a defective pair--since the right side of the headphones isn't working, I have decided to not panic (tech will always break down eventually, trust me I know) and patiently wait for either a replacement, or a confirmation call from the headphone zone inspection team as was promised(once I ship it to them) --following which more will be added to this review along with what rating I think this headphone deserves.

Not buying an AMP along with these headphones was another naive mistake on my part, since I assumed the DAC built into my ROG phone 5 and PC would suffice to power these 18ohm cans. This I think has now been rectified with a purchase of the iFi Hip DAC 2, which should technically be enough to drive the planars if I understood the spec correctly. Could this also be why aside from the low volume, there is no sound out of the right earpiece? If so, it would save me a lot of hassle just to wait for the amplifier to test things out rather than ship these back to you guys :) A quick response from anybody familiar with this issue would be a great help...

I am writing this after spending 4 hrs with the Edition XS.
I am not into headphones, never was. The idea of having a heavy thing on the head to listen to music never thrilled me. I have a serious stereo setup. Like, seriously serious and I love it. The problem is, I don't get much time to be in that perfect listening position more than 3-4 hrs a week. For my love of music, I decided to get some portable gear. So, I started with a mid-range Fiio triple driver earphones (don't remember the model) and the R2R Cayin RU6 USB DAC+AMP (the RU6 is brilliant). I liked the experience very much and thought of upgrading (the problem with all audiophiles right). After some research, I zeroed in on the Hifiman Edition XS (not the standard headphone tech) and Chord Mojo 2. Unfortunately, I couldn’t get the Mojo yet as it went out of stock by the time I wrapped up my research and decided to hit the ‘add to cart’ button. Thus, I hooked up the Edition XS with the RU6 that I have (yes…I had to change the setting to high gain and crank up the volume to 85% to drive the Edition XS) and played some of my beloved hi-rez/lossless tracks. Now the difficult part – describe the experience. I’ll just say – It made me smile and I felt I am listening to my primary stereo system. Beautiful soundstage and excellent clarity across frequencies.
The only thing that I feel could have been better is the head band. Something like Ananda would have been more comfortable.
Now I am thinking, what have I gotten myself into? What next?

Delivery - 5/5 (delivered with in 24hrs) 

Sound - 5/5 for me. Using these for more than 3 days it gets better and better. Very good sub bass. Detail retrieval is very good - Played rdr2 with this and it's like I'm "in the game". 
some songs rcmd: 
Men I Trust (garage sessions)
VULFPECK /// 1612 , Dean Town
AC/DC (Live At River Plate, December 2009) 
Kendrick Lamar - N95 , Alright.
Mac Miller - Self Care, Good News.

Built and fit - 3.5/5 . Headphone wire and pads are meh (notbad/notgood). It's very comfortable and perfect fit for me but this headphone has a very weak clamping force - this is the only downgrade / dealbrake for some, I think if you sneeze hard it'll fly off from your head. 

HiFiMAN - Edition XS

I don't need to write a lot about it because a "whole lot" reviews are flying around on the internet.