As an old duffer I much prefer metric.
Curious fact: the inch (and foot and pound weight and others) are defined in the UK by their metric values. Somewhat surprisingly the same is true, for the inch at least, in the USA. Also, historically the yard (and therefore the foot and the inch) have shrunk over the centuries, the yard used to be about 10mm longer. The reason was that the authorities kept changing the standard definition.
Prior to Carol Morgan's 24hr record last year I was asked about the criteria for valid peaks. Really hard to verify things when the criteria are in feet and the maps are metric. Will have to consider metricating the criteria.