Agree fully with loco4viento
The fast and efficient open cell foils, can generate HUGE amounts of power pr m2, some of them.
But also way more difficult to master, thus not really finding use in the broad market
I remember some of the really powerful small ones, 4-5m2, that could kick ass like you've never seen before !
Such a massive acceleration and power when flown fast, that could pull like you have NEVER experienced
Have also seen 100kg guys getting tossed around through the air, over the water, back in the days - with these.
Also incredible powerspikes (especially if you dont master it fully), which is both good and bad of course.
But they are WAY more interesting (and difficult) to fly
- instead of our super boring LEI kites
Dont use these myself now, as I am mostly into waveriding - but damn some of these kites can REALLY perform, if you can handle them
For light wind freerace or lightwind waveboards (not DTL riding, just having fun), I've used 14 and 15m2 LEI (light wind) kites now and then (77kg), but always ditched these again, as I found I could go just as early with a good 12 or 13m2 kite, but without all the downsides !
Off topic ? Hmmm, maybe not, because IMO size is NOT everything, in terms of light wind ability (part of it, but not only)