I bought these on a whim. I've previously owned XM4s, XM5s, Airpods Max, but my daily driver is the Nura True earbuds and Audeze LCD GX at home. Here's a review from me.
Sound: Phenomenal sound overall. For me everything is well positioned, the headphones are a little dark but I don't think they sacrifice detail in other areas. I used the sound check EQ using a couple of different songs and it seems like I generally prefer them with a treble boost. My EQ is 0, 0, +4 in the 3 band EQ and I'm very happy with the sound after EQing.
I listen to a mix of punk, rock, electronic, folk, instrumental and so forth. A bit of everything really. My favourite bands are Turnstile, Pup, Royksopp, Wet Leg, Idles, Pup, Let's Eat Grandma, The Staves. So far there's nothing that I've thrown at it that I've disliked its rendition of, the bass is impactful and feels fun, while the mids and treble feel accurate. It's hard to complain about anything and I'd say they're a very enjoyable listen throughout.
Against the Sony or Apple competitors, I'd say the Momentum 4's better and not by a small amount. They are leagues ahead of Sony and Apple's headphones in this area.
Connectivity: I I've had no issues with the bluetooth connection. It's easy to connect to my iPhone or Switch. I was disappointed to see that they do not have a 3.5mm jack input built into the headphones. I'd like to have this so that I could plug a 3.5mm mic into the headphones like the v-moda boom pro. Something you can do on Sony's XM5s.
I did use them a little bit over the 3.5mm jack and I was happy with the sound. I can't see myself using them this way often though, partially because of the 2.5mm input (I know I could buy an adapter) but also because I don't really have much of a use case for that since I'll fall back to the Audeze when at home.
App and Controls: The app and controls do not offer a good user experience overall.
- The 3 band EQ is very limited.
- The apps controls do not always work, especially when I first put them on (I think this is because they are not always being detected as being worn by the usage detector
- The usage detector that intends to pause and resume your music when you game them off seems to work inconsistently, and causes other issues like the one above
- As a left handed user, having all the controls stacked into the right earcup is quite unpleasant. If I'm carrying something it's usually in my right arm, leaving my left arm free to use my phone and things like that. It's just not good design for lefties (much prefer headphones like the NuraTrue in this regard, which allow you to control from either earcup)
- I struggled to update them initially, the update failed 3 times despite being left unused and connected to my phone and the app while updating. Not sure why this occured but it's very frustrating because the updates are very slow (pretty much an hour for me)
- The controls, even when being registered are quite awkward, in my opinion. Pinches and swipes aren't my preferred method of interaction on an earcup, and I might prefer to rely on taps and holds. The app offers no flexibility, no customization of different gestures.
- The adaptive ANC offered in the app does not make any sense. It is constantly adjusting the ANC level and I can never make sense of why. I cruise around with these on my head while longboarding and I can hear the longboard wheels running across the floor at varying degrees of loudness across a 30 second period. It doesn't just fail to function as intended, it's actively annoying.
Just on the inconsistent controls one thing I wanted to add is that my use case for headphone is often while cruising around on a longboard. When I'm doing so I like to have a pair of headphones with very quick access to transparency mode because it helps me hear traffic at junctions and things like that. I'm never skating in the road but I do skate across the road from pavement to pavement. At junctions I like to be able to hear if there's any oncoming traffic, it's not the only sensory input that I rely on, but it makes me feel safer. Unfortunately I found the Momentum 4 to be too inconsistent to use in this way because
a) double tapping to enable transparency and stop music playback doesn't always work
b) I find the double tap isn't the nicest interaction to begin with. On my Nurabuds I set transparency mode to a single tap on the left earbud. So with my left hand (again, I'm left handed) I can tap my ear and continue skating on.
I think really the important thing for me is having customisable controls. You can't reliably predict everyone's use cases all of the time, so control customisation lets the interaction design meet the user rather than the other way around. It would be good to see this added to the app.
Noise cancellation and Transparency: I find it to be very good. I don't get the pressure effect that I've heard others talk about, and I find the ANC to be very effective to a point that I can sit in near-silence in loud traffic filled environments. When music is playing I will rarely hear anything but the music, and any surrounding sound will be very quiet. I think the ANC works well.
Transparency too, I think this is excellent. I can have full conversations with people in shops and whatnot without straining to hear, I think this is very good. I used transparenccy mode to have a chat with my girlfriend yesterday as we walked home, and had no issues participating in conversation. I wouldn't normally bother in fairness since I know it comes across as rude either way, but I kept them on to test the transparency and because it helps keep my ears warm on a chilly British evening.
Aesthetic: I bought the white ones and I like how the look. I think they're a pleasant fashion accessory that I can get to sync up with a lot of different outfits. From smart suits to street wear, I think they look great. I took a quick photo of me with them on for this review. Sorry for looking so annoyed in the first photo.
Comfort: I find them to be quite comfortable, but not perfect. The headphones are very light weight which helps a lot, the earcups are sizable which is good, and the headband feels weightless. However, I still have to be quite careful how I position them around my ears otherwise my ears begin to ache after a few hours. When positioned more carefully I can get the earcups in the right spot to avoid pressure on my outer ear and therefore, no long-term discomfort. It's just a bit more effort than it is with headphones with larger earcups that fit my ear more easily.
The problem with this, is that the way they fit into the case requires that you constantly reset the position of the earcups. You seem to have to put them into the shortest position possible to fit them back into the case. This means you might have a perfect 'fit' but you have to effectively recreate this each time you have them enter and exit the case. It's not too big of a deal because I don't thin the ideal comfort fit is that strict, especially as they're light weight, but it's an extra little annoyance.
Build quality: They're plastic so that obviously has pros and cons to durability. On the one hand they can bend and twist easily, which helps them resist impacts and pressure, but no plastic headphones I've ever owned survive more than 5 years. All of those bends and twists eventually take their toll and something gives. I can't really say that will happen here, and realistically I don't think these types of headphones are supposed to be a life-time investment, but in my experience headphones made from other materials such as metal tend to last longer through daily use.
Call quality: Part of what incentivised me to buy them was the fact that the mic on my NuraTrue earbuds is not very good. So when I'm walking the dog or skating I can't easily chat with my sister or girlfriend. These solve that, I can be cruising on a longboard in the wind and my girlfriend seems to have no issues understanding me. I haven't performed much of a mic test myself, but I've had no issues and people have reported me to sound very clear.
Battery life: 60 hours is such a blessing. I can charge them once per week, perhaps two! As someone who is neurodivergent with difficulties with organisation at times, this is a life saver as regardless of whether I'd planned to use them the day before, they're almost always good to go.
Case: The case is durable and seems like it would be pretty effective protecting them. The only downside I would say is that the case is in itself, made of a very nice material that is likely to stain. This means that I want to protect the case itself from the contents of my backpack, which could include things like leaked drinks and other food items. Basically, a non-porous case would be better, something you can wipe things off of more easily.
Overall: Excellent sound quality, good ANC, bad controls and app experience. I really like the aesthetic and I think the build quality is good. Honestly despite some issues I really like them a lot. The sound quality is unparralled in its product category and while the app experience isn't great, you can easily ignore most of its issues, EQ them into a good spot and just go. The controls are bad relative to their competitors, but I wouldn't say they're unusable, they just take a bit of getting used to, and hopefully these are kinks they can work out in software. I would strongly recommend them.
You can also use them wired in 2 different ways (3.5mm cable or USB-C)
is there any chance in future software update that we can turn off ANC completely ( not reducing but just off ) 
