I wanted to update my review to describe my disappointment: these earbuds are amazing, until they randomly stop working. The sound quality is superb, and the latency is so low that I can play games using them. But there's something seriously wrong with them:
I bought them on April 2023, and after 6 months only, the left earbud just stopped working for absolutely no reason. I didn't damage them, didn't splash them with water, didn't do anything. I was listening to some music, and the left earbud just went silent.
I followed the factory's instructions and reset them multiple times, but no success at all. I claimed warranty, and got a brand new pair as a replacement. They worked great for 6 months, then the right earbud stopped working. I was playing a pc game using them and they were totally fine, then I finished and put them back in the case. After 2 hours, I put them on only to find that the right earbud no longer works. It gives very faint ticking sounds, but no audio at all.
I have no idea what's going on, and I saw some online forms with people complaining about the exact same issue. And I don't know why 6 months seems like the magic number here.

The one headphone stopped working after only 4 months. From what I saw on the internet, this happens to many people around the same time.

Very good earbuds especially for their price. Very clear and crisp sound, you can distinguish the instruments in the music and you can adjust them with the Sennheiser app. They also have good sound isolation, I used them at the gym with lots of noise and I couldn't hear anything else apart from the music from my phone.

The microphone doesn't record in good quality, but obviously you don't get Sennheiser for the microphone. Also, they are relatively bulky and not as comfortable if you lie on your side

I come from wired Sennheiser headphones that cost 30 euros to these, so I can't make many comparisons, apart from the overall sound quality of the company compared to other wired headphones from 4-5 years ago.

So as far as sound goes, I am satisfied, I think the quality and volume are very good! I tried a friend's cheaper bt earbuds, the bass covered the entire sound and it sounded like it had interference in the highs. You get what you pay for.

After the initial connection with my phone, every time I take them out of the case, they connect very quickly! Only 1-2 times when I took them out, only one of them worked, so I put them back in the case and took them out again and the problem was solved.

The app is also good, I didn't need to change the earbud tips. But be careful: to have sound quality, you have to choose the right earbud tips and fit for your ear. It's just the way it is, otherwise it won't fit inside your ear.

I haven't run with the headphones in my ears, but generally I don't think they fall easily. They are relatively bulky (of course, very lightweight) but I prefer it for better handling.

Now, as a hands-free device, it's mediocre, others can't hear me perfectly, but I didn't buy them for that use anyway.

The only disappointment is the Sennheiser app for the headphones:
- it takes a long time to connect to the headphones even though my phone's Bluetooth is always on
- if it stays in the background for more than 5-10 minutes, it's as if it disconnects from the headphones and I have to wait for it to connect again in order to access the equalizers (the music keeps playing, of course, the app is not necessary)
- the controls of the equalizer are terrible in both versions
- overall slow response, installed on a new mid-range smartphone

Overall, satisfied, I just hope the app fixes these issues in a future update.