I like video shot from the 3rd person or "backy" mounts. I'm making one to use this year for my GoPro. Hopefully it's not a POS I waste $90 on..... I've been using the Go Pro "Chesty" mount for a few years. It's ok...........but the constant view of the chicken loop in frame is annoying. The plus side is you don't even know you're riding with it. Very comfortable. It's a great option for getting footage of OTHER riders too.
Not a fan of the fin mount footage at all. Everything I've seen is just spray, violent movement and maybe a second or two of coherent footage. Dimitri has used a few decent fin mount clips in his vids though.
I do like the strut mount footage for showing nice locations and great water. Not sure if the GP's field of view is too wide for a strut mount shot? A few vids I've seen with the strut mount the rider looks like an ant.
Line mount stuff is fine as long as the finished video has been processed with a program that takes the shake out and corrects the view to always be horizontal. There is nothing worse than watching line mount vid that shakes around so much you're ready to puke after 90 seconds of viewing.
Blair Witch style shaky footage is weak sauce.............even in kiteboarding.
Board mount is a great spot. When mounting to the board place it dead center in between your fins and angle the camera slightly up about 5 degrees. You will get a great view at that angle.
Helmet is great as long as you keep your head relatively still. Too many kiters with head mounts are constantly moving their heads...looking up at their kite...behind them....etc....and it makes for bad video.
Strut mount is my favorite because I like to see the surrounding environment from 70 feet up.
I'm not a huge fan of line mount but that's just me. I have seen some good line mount videos where the camera was angled just right and a lot of the kiting environment was captured.
Chest mount flat out is the worst because you will video your hands on the bar the entire time.