The choice of speaker brand was easy, just the model to consider. As they are for Atmos duties and not mains, the decision was easy and confirmed as the best choice by CSW and Bowers & Wilkins.
Fitting was easy. Very well thought out by B & W having a template for the cut-out and frame that inserts in the ceiling with 'dogs' that are swivelled into place and pressed down onto the top of the ceiling after inserting the frame. The frame has the wire connections so this can be done before inserting the frame into the ceiling. After inserting the frame it is just a case on inserting the speaker into the frame by orientating it to align with the connectors and pressing home the three retainers. A breeze. The hardest parts are selecting the correct locations for Atmos whilst avoiding mains wiring, pipework, Structural supports, ceiling plasterboard battens and running the wires to the amplifier.
Took about a day for four speakers, taking my time and double checking everything including using a continuity tester to ensure correct wires went to each speaker and the polarity was correct. I used two lengths of four core install cable.
Very neat once completed with the grills on.
I recommend CSW whole heartedly too. I have reviewed them at length elsewhere.