Fernando at Xtremewinds. That is where you want to go in Aruba. I just returned from 5 days of kiting there. Here is a synopsis: 2 riders, one independant and one beginner. The beginner took lessons with Fernando, boat supported, with radio helmet, while the independent rider kited freely knowing that Fernando had my back. You want someone keeping an eye on you at the Fisherman's huts with the offshore winds. Fernando is the guy to do that. He is in the boat, following along, not too far away if s#!% goes wrong. The other kite schools at the huts had beginners drifting off to sea on their own. I saw one frantic brit over by the shipwreck, board was lost, drifting away. No support boat in sight. It eventually came, but way too late.
I then took a jump lesson with Fernando. He had me flying in no time, while keeping an eye on my almost-upwind-riding buddy. He made some tweaks in my riding style that were spot on. He is a hell of an instructor. The best thing is that he cares and wants you get better. We stayed at his apartment, and most nights we drank beers together on his sweet back porch and got essentially a free debrief/chalk-talk about the day's events. That was invaluable. He is a great host and makes you feel truly welcome. Of course, it is a business for him, but his prices were TOTALLY reasonable, and he threw in lots of freebies because he really wanted to see us advance. Which we did. He also sent us to Boca on our own and told us exactly how to kite safe there. He could have said "no, you need a lesson at Boca" as it is a difficult spot with direct onshore winds. But, he assessed our skills and sent us off to rage.
As for the other schools, I can only tell you what I saw: An instructor crash a kite into a boat; an instructor launch a kite directly into mine on the beach, schools putting people on boards that could not even fly the kite yet. The peace of mind you get in a lesson or supervised session with fernando is awesome. He keeps you safe and gets you to the next level.
He is the ONLY service I would use when I go back to Aruba. Happy to offer more details if anyone is going there. Yes, the kite spots are not great, especially for beginners. But Jesus, the wind blows, all the time, hard. If you get skunked there, then you have not been living right.