Fixed bridled open celled foils like the Blade III have the most power per sq/m for sure, but get em wet and it's all over.
If money doesn't matter I would say get a Flysurfer Speed 17m.
Deftinitely the best lightwind water kite around.
I'm thinking of selling mine because it's too powerful for my weight, 67kg, I think I would be better off with the 13m. I get overpowered at about 13 knots!
There is a big Guerilla on ebay at the mo I think, 18m? Nowhere near as powerful, but cheap.
A while back I was thinking about getting a 13m Venom for when I'm overpowered on my 10m Speed. Shows how venoms are less powerful for their size. 19m Venom is your best option for an ARC I reckon. Try
www.foils.nl/ for more detailed info.