The sound quality is really very good. Significantly more precise and more natural than for example the SE 535, which I had previously.
From the sound signature not unlike the SE 425, but in each discipline a bit better.
What's not at all, especially not at that price, is the miserable quality of the handset and cable, as well as the underground Customer Service Logitech.
The first purchased in October pair disintegrated after a few weeks. You could remove the cover of a listener, because the bonding was apparently miserable.
Both! Cables were broken after a few days despite only ordinary burden. The contacts with the listeners wobbled on from the very beginning. The exchange of views on the Logitech Hotline cable took about 2 weeks. The phone they would not swap!
Amazon did it then without hesitation.
The second handset I ordered then in December. I thought to have been unlucky with the "first series" or whatever.
Also in the second receiver the cable went kaput after 4-6 weeks and even both.
The customer service from Logitech was difficult to achieve and even harder to understand the facts of term.
Anyway, warranty service for the cable were wordy rejected.
Again helped me out of trouble and Amazon took back the entire handset.
I can only summarize that the quality of workmanship, in particular the cable is absolutely bad and advise for this reason only of the purchase.