There are two types of refrigeration manifolds, an analogue and a digital refrigeration manifold. Analog gauges have been used for a long time, many generations of professional cooling and heating technicians have worked with them. The professional technicians who have used analogue gauges can be able to tell everything they just by looking at what the hands tell them, they don't even have to look at the complex charts. However, doing this can turn out to be quite the problem. As the readings on an analogue gauge aren't the perfect ones and if the technician gets it wrong the problem could potentially become a bigger one.
Digital gauges are preferred by many technicians in the modern day and age because they give them results much faster. The results that are given by a digital manifold are also much more reliable and accurate. They also provide a lot of other features and readings, without the need of complicated charts and conversion tables. Meaning, that errors are less likely to occur. The only problems that technicians have found with digital refrigeration manifolds are that they require some training in order to be used properly. If you aren't well trained using models that have other features added to them can confuse you and that could complicate things.