Hi,
We just got a new Brother NX-450q and we love it.
First off the auto thread cutter is AMAZING!!!! I could never go back. We have 2 machines now and if my wife is on the good one id rather wait then use the old one.
As for the foot pedal, i used the button rather then the pedal for about a hour before i went back to the foot pedal.
I just feel i have so much more control over speed and starting and stopping. I do not think ill ever use the button again.
And ass Mimmy said the knee lift is just as useless for me.
Hope that helps.
All the best
TheFatQuilter