Here's my review - from the viewpoint of a total basshead.
Rock, pop, hip hop, low fi, electronic. - All sound fantastic to me on these. Especially with artists that really push the bass in their mix (Billie Eilish is an unexpectedly great example.)
When pushed with the Wavelet EQ app on my Samsung A52 these sound better than anything else I've owned - including the huge wired "Princess Leia" over-ear Sony MDR-XB700 (don't confuse with the modern XB700 which is a small wireless one) and the wireless over-ear Sony XB950BT.
But right out of the box they have around a 0.6db volume difference between the left and right ears and issues where the cable meets the 3.5mm connector.
I would not purchase these from anywhere where it would be difficult to return them if you get a dud like mine.
BASS:
Absolutely killer deep bass is possible if pushed in EQ, which is not something you can do with all earphones. Many others just turn to garbage when pushed even less than a quarter of this. I included a screenshot of my EQ settings.
I don't think I have any significant hearing damage. Maybe I'm just insane. Or maybe I'm just an average basshead?..
With these settings can still hear the details really well in the rest of the track and to me this sounds amazing.
For me the bass carries the track - but I still can hear the vocals and other instruments really well.
I'm just extremely sensitive to high frequencies and often find them pretty painful to listen to.
(Note that Wavelet is the best EQ app I've used and is comparable to the EQ abilities of a dedicated portable amp/DAC device (ES100 Mark II). So if you're listening direct from a mobile phone see if you can get this app specifically. Other Android EQ apps tend to be either mediocre or useless. It varies a lot between apps and also the actual phone used).
SUB BASS:
This has so much sub bass that (even at what I previously considered "okay" listening volumes) my ears will ring for a few minutes after I've been listening for an hour or so. Not something I've ever experienced before. After a couple times this happened I learned to lower the volume a bit more. Lol
(I'm EQing the heck out of these so it's probably not like this right out of the box).
Honestly incredible bass and sub bass. And overall a really good clear sound.
ISOLATION:
Decent noise isolation. I didn't do any scientific comparisons.
COMFORT:
Not 100% perfect for my small ears but pretty good. Mostly just the cable hook isn't in the right place for me and that pulls upwards on the actual ear buds. but if I want extra comfort in bed I just don't put the ear hooks over and just leave them loose and they fit just fine.
With many other earphones I use the middle size of tips but with this one I had to use the smallest.
CABLE:
Pretty basic braided cable. Feels cheap and lasted only a few weeks until it was unusable.
If I walk around with the hooks loose then there's microphonics noise from the cable.
With the ear hooks used properly there's zero microphonics unless I actually scrape my thumb nail on the bumps of the braid.
There's a mic and a pause button on the cable. And a bulky plastic piece where the the two sides separate.
CONCLUSION:
If you only use the OS1 carefully in bed then these could be a super fun way to spend $20. The sound is killer for even the most demanding of bassheads.
The OM1 or OS1 Pro models both feature a removable cable so that's probably a much better choice.
I have an OM1 on the way.
I pulled as hard as I can. Tried with a screwdriver even. They aren't removable.