I did this exact swap few weeks ago.
B6 55” to the cx65
Got mine from richer sounds 6y guarantee. My impressions are
Sound from speakers is certainly improved
Picture is better (not massively so )
65 “ is perfect for me.
Few extra setting ref sound and picture options
Don’t do any gaming so can’t comment
But I still see blur when watching sport ie
Snooker the balls blur when hit
Footy same with football when kicked it blurs across the screen slightly
Watching Netflix thru the button in the magic remote is fantastic. Allows Dolby sound and vision on the cx65