Both has its pros and cons: Digital machine is highly sensitive,a twist of hand, surrounding, all tend to affect it, sensors may not all the time be very accurate but may over do its job by showing bit higher or lower this leads it to erroneous results. Though it gives a pretty fair idea. For manual one, it's preciseness depend more on perception of the doctor, while it does away with mechanical error due to sensors, it may let human error creep in, moreover when you have quiet a number to manage, digital ones serves better.moreover with whatsoever maneuver you can't measure your own bp Digital :easy to use, works better in hospital setup and ward where there is a large number of patient, can be used to measure one's own bp without much help, less prone to human error or error from fatigue, etc Manual : depend on user, less prone to overly sensitivit / mechanical issue, needs no power source like battery etc,