Hi macyui,
I’m assuming that you mean the massage system in an adjustable bed?
In my experience … none of them would be what I would call a “massage” and are more of a “vibrator” that moves underneath you and can be programmed in various ways for speed and intensity and movement depending on the model. They can certainly be relaxing and soothing but the effect of the “massage” will also vary depending on the type and thickness of the mattress that is on top of it.
The best way to see what they feel like would be to do some local testing on various models.
There is more about choosing an adjustable bed in post #3 here and the adjustable bed thread it links to.
Phoenix