A lot of the appeal of high quality tools is how they feel in the hand and whilst in use. That means it can be a really personal decision - especially when it comes down to weight and action. I always reach for our pair of standard size GR Pro secateurs. Louise usually goes for the Sentei's as they are marginally lighter and she prefers that.
We were discussing this subject with Niwaki recently and they immediately asked if we had ever tried a pair of the GR Pro Lightweights. These are a lighter version of the standard secateurs with a smaller head and a softer spring action. They compromise a little on their cutting strength as a result but are often chosen by professional gardens who might be pruning all day.
They are also perfect for gardeners with smaller or weaker hands, as well as those needing the precision that the slender blade provides