Hi wukong543,
I switched your post to the adjustable bed thread which is a more relevant topic and I would start with post #2 here to help you make some meaningful comparisons between adjustable beds.
In terms of the strength of the motor I would probably go by their rated weight capacity.
It’s been a few years since I made some careful comparisons when I purchased my adjustable bed but at the time I tested them the Reverie had the strongest massage IMO but I would think that with all the new models that have come out since then that this may no longer be the case and I would do some testing between different models to decide which of the newer models have the “best” massage (although I would still consider them to be more of a “vibrator” than a “massage”).
I also didn’t think that any of them had a noisy or intrusive motor and all of them were relatively quiet but in general terms DC motors will be a little quieter than AC motors but AC motors will tend to be a little stronger. In most cases you wouldn’t be using the motor when you are asleep anyway.
I also don’'t remember noticing any significant difference in the speed of the lift and none of them were particularly “fast”.
Perhaps some of the other members here will have more recent experiences than I do and can share their thoughts about some of your questions as well.
Phoenix