Pin lock is the main check
The best rangefinder should lock the flag before a playing partner starts second guessing the number. Fast vibration feedback and stable optics matter more than a long feature list.
Display readability matters in UK light
Low winter sun and grey skies can make cheap displays harder to read. We prefer rangefinders with clean contrast, simple numbers, and a case that can be handled with wet gloves.
Slope is useful but not everything
Slope helps on practice rounds and hilly parkland courses. Tournament golfers should choose a model with an obvious external slope switch, so there is no ambiguity before a competitive round.
What to spend
Pay more for optics, stability, and warranty support. Do not pay extra for features you will ignore after the first two rounds.