Like TVs and pretty much everything else these days, most modern transceivers are fully digital. Digital transceivers are fitted with multiple antennae and processors to present data as both an audible signal (a beep) and a visual display. This visual display will usually indicate both the direction and distance to the victim and should adapt very quickly to changing signals. They are more intuitive to use than analog transceivers and so recommended for novices.
Totally analog transceivers are relatively hard to come by these days. They only have one antenna and typically only present the user with a beep that gets louder as you get closer to the victim. In general they have larger search ranges than digital ones but require a fair bit more expertise and an understanding of electromagnetic flux patterns (it’s not as complicated as it sounds) to use properly.
We’d always personally always go for a digital one unless you’re already well accustomed to using an analog one.