A laser rangefinder and a GPS unit will both tell you it is 152 to the pin. The difference is in the question each one is built to answer.
A rangefinder measures a precise line-of-sight distance to whatever you aim it at — the flag, a bunker lip, the front edge. It is exact to about half a yard, and it forces you to pick a target. That precision is why it wins for approach play: the gap between 148 and 156 is a full club for most players.
GPS answers a wider question — front, middle, and back of the green, carry distances over hazards, the shape of a dogleg you cannot see. It is faster on the tee and better for strategy, but it will not tell you the pin is tucked four paces behind a bunker.
Buy the tool that erases your most expensive miss.
If your scorecard bleeds on approach — long, short, never quite pin-high — a rangefinder is the cheaper stroke. If you keep short-siding yourself or airmailing greens you could not see, GPS strategy is the fix. Many players eventually carry both, but start with the one aimed at your actual leak.
Whichever you choose, commit to the number. The worst distance is the one you talk yourself out of after you read it.