Two devices can be connected to the headphones at the same time. Switching between them is possible without any problems. Pairing and connecting is running smoothly.
The headset has a switch that lets you turn it on & off and control the Bluetooth search. Additionally there are 3 buttons in the back, below the right auricle, which can be easily felt due to the different size. These can be used to control the volume (louder/lower), pause/play, song playback (forward/back) and calls can be accepted and hung up. The buttons are easy to reach and offer all the controls you need.
The most important thing is of course the sound! The perception of sound can only be subjective. Although the Bose QuietComfort 35 is a comparison for me (as an audio tester) to several other products, everyone has different preferences. That’s why you should just go into the shop and listen to each other, my opinion should not have any claim to absoluteness. The other day I was in a Saturn where all headphones (50+) were connected to a subclass amplifier and therefore all models sounded miserable. One should therefore also think about the area of application before making a purchase. Many smartphones (especially via Bluetooth) cause sound loss.
The sound is harmonious according to its price range and what one is accustomed to from Bose. The sound is very good. The frequencies are well tuned to each other and can be heard comfortably. The bass is not too strong/whummy, like many other headphones. To perfection I lack a little dynamics in the midrange and a more precise bass. The potential volume is more than sufficient. The sound quality only decreases when the volume is set to a high level, which can damage the ears. Once you have listened to this quality league, experience shows that you stay there even though the prices are higher.
The price-performance ratio is therefore to be rated as worthwhile for sound fans and less recommendable for “casual listeners”.