I'll bite, This topic always goes pear shaped on this forum and has been done before......but for entertainments sake...I swing both ways!
For shallow river mouths kiting winds hands down, especially in a light wind area where you need big boards/sails/fins and none of that works well in shallow sandbanks, unless you want to break your gear and neck, eg Cotton tree, noosa river, caloundra bar, especially outgoing tides
Physically and stoke wise I get more from windsurfing, kiting is way easier physically and to do stuff like below is dead easy, (me at C/tree) if i did that windsurfing I'd be super buzzed, as its much harder to do.
In the past I found there was little cross over, but now I'm often tossing up on what to do as the range capabilities of both sports equipment is so good now, it's light time to kite / windy time to sail line is often very blurred.
I don't like kiting in strong winds, just too much down side when its super strong, i figure I've used a lot of my kite luck up back in the early days, so no need to push it, if its 'properly windy' I always windsurf.
A down side to the shallow llghtwind/rivermouth/scene is that every man and their dog is doing it now...these places are often OTT crowded, not fun when there are 25+ kites up and a heap of beginners crashing all around you! So you need to skill up to handle open water and downwinders (which are the best)
It's all good, if the world did more of each it would be a better place, i don't buy into the us/them thing, just make sure you get lessons, its not like windsurfing, mistakes can have massive consequences.. book in with one of the local schools.
Now to stir some ****....:)
I find kiting is bit like masturbation, it's easy and convenient, feels good and you end up with a smile on your face, but it kinda feels like your cheating , it's not as good as the real thing, which is often much harder to obtain but the reward so much better.:)
A lot of girls kite? ....probably much more convenient than finding a ......windsurf school :)