They are quite easy to pair, long pressing the button on the side of the case will put them into pairing mode, then connect to the phone and then opening the case or pressing the button will start pairing next time.
The earphones site on the ear much like the fruity company's original pods, so your mileage will vary on how well they fit or fall off. Personally in-earphones work better but lots of people are happy with this kind of design.
The earphones are Bluetooth 5.0 and support HD sound. They charge in around an hour and will play for 4 hours, though popping them into the case (which sarges them) allows up to 14 hours of play.
Each earphone has an infrared sensor and 2 microphones and tapping either earphone will answer a call (or hangup). Tapping twice on the left earphone will activate a voice assistant while tapping twice on the right will pause binaural mode and a single tap will activate single play. Removing an earphone will pause music play.
The binaural/single ear play are so it's possible to lend a colleague an earphone and they can listen to the same music you are (or listen to something else).
The dual microphones are used for noise cancellation, but as the earphones are only semi-in ear, that's mostly for speech etc and not for blocking outside noise during music play.
They are available from the Mi UK Store for £69.99 which is a bargain compared to their fruity counterparts, though Chinese (original) imports inc shipping can be had for around £30-40 (with a silicon case), the 2S are £10-20 more expensive.