thought I would offer some balance here as to why I think foils are a fad.

In the same vein as they jumped on SUP even in zero surf areas (spend $50 on an old windsurfer long board instead of 2k), now they are trying to flog foils.

I used to waterski foil (airchair/skyski) for several years. I did it for a quite a while and whils no ledgend I was there from the early days and tuned foils etc. I also rode with the AUS and occasional world champ. the kiteboard foils are the same just bolted on to boards. Mike murphy introduced laird hamilton to foils and he rode them at jaws.

The sit down versions behind a boat can get fairly high air due to the leverage you get. Being strapped in to the board sitting down has it's advantages as when you crash it's hard for the hard, sharp metal foil to injure you. That said you still need to wear a helmet.

When the stand up versions came about it was a lot easier to get wounded by the foil. The stand up versions have never taken off.

Now they have kite foil boards and kite winsurfer boards. Sounds awesome but if you know the limitations and what to look for in the videos

The limitations are - the foils are very directional - you have to land in the exact same direction (the strut has a wide knife like surface area) so if you land slightly off you crash immediatly.
When you crash it's a dead stop as it all becomes a sea anchor. you dont skip, decelerate etc as you are strapped to it. you completely dead stop. this can hurt.
they have a terminal velocity, and a fairly limited speed range, although I think this could be developed. But the faster you make it the less lift and low speed performance.
They are not the rough water tool everyone thinks. you can glide over a bit of ripple. get high chop though (i.e. enough wind to kite in) and you have to keep the foil well below the water otherwise as soon as it cavitates or breaks the surface you loose all lift and sink down onto the conventional board. You sort of have to raise and lower it to keep the foil at the appropriate depth. Too low and the waves slap the doard part. to high and it areates and you sink straight down/ slow right down.

You need fairly deep water. Any scratches, nicks cuts in the reasonably soft aluminum are quite significant - water is much denser, and you can really feel this effect. So too as the foil tarnishes. a good polish does wonders.

Because you need deeper water if there is wind you are back out in chop.

The sensation for the sit down at least is like balancing on your school chair on two legs.
It's a bit of a sensation gliding over calm water for the first couple of goes, but once you have it down, it's nothing extrodinary.
But when you start trying to incorporate ariels, the combination of having to balance your weight fore and aft (to control the height of the foil) landing in the same direction with the foil at the correct elevation angle, and the resulting few seconds before the foil starts to work and generate lift again will mean it wil lbe very difficult and very unrewarding as a tool for an uncontrolled enviroment like the ocean. Noone does anything good on the stand up ones behind a boat at a constant rate fo pull in dead flat conditions. there is just too much to control.

So their only application is 10 knots? but you need deep water (dont scratch it). then as the wind picks up (it's fairly deep) so does the chop. Fun factor goes down. and at the end of the day you are mowing the lawn. you might be able to point high. MIght be ok for yacht style match racing (yaaawn).
For me in marginal conditions I think you are far better with a wide board in the shallows (flat water) and pulling moves having fun. Or do some jobs around the house so you can go when the wind picks up.

The surf retailers are always quick to jump on any new bandwagon because it makes them money and they are under pressure from the distributors to do so. even when it is an ordinary product. They are always trying to bring out new things to make a buck. I saw on here som dutch dudes with a kiteboat for $5k euro. It looked like you had to hold the boat from the ground to relaunch in strong winds. and it's 5k euro.

anyway I thought I would write this in case someone has their heart set on spending 2.5k or whatever thasking price is because they are in love with the idea of a kiteboard foil. The promise is just a long way from reality.