Purchased mine yesterday from John Lewis, £263.00 with friends/employee discount.
I am no audio file but I have owned Sennheiser Momentum 2.0 Wireless, also Bose QuietComfort 35 II, also (Beats Studios and Pros, Please don't laugh at me).
The Sony WH-1000XM3, are great for people like me who are Bass Heads but also appreciates some of the higher electronic synths sounds you get from music like Detroit/Chicago House. Even I had to use the Sony connect app and set the headphone to increased Treble, as the bass was sometimes a little bit overpowered for my taste, which is saying something.
My opinion, the XM3 noise cancellation is better than the Bose35 II, but the noise cancellation vacuum effect is more noticeable on the SonyXM3, especially on lower volumes.
The Bluetooth works great, I live in a 3 bedroom house with a ground and first floor and can have my Samsung Note 9, Phone on the ground floor and be anywhere on the first floor without dropping the connection.
The build quilty is great, even though it is plastic you can clearly see/feel how premium these headphones are, I was considering the White pair but very happy I last minute opted for the Black version (Timeless Classic Look)
Also, I was very concerned about the reports of broken hinges and other faults with these headphones, but from what I can see if you are going to lovely use and not abuse them you will have no trouble. Also, John Lewis will directly cover any manufactures faults within 2 years without you having the send them back to Sony.
All in All, I am very pleased with the Sony WH-1000XM3, if you are considering purchasing them, just get them you will be very pleased.