Alright I'll put in my tuppence.
since dd started school I've used adult shamppos on her. I used to use the loreal kids blah blah shampoo but realised that her hair was thicker and longer than mine and the kids stuff just didnt do a good job.
Shes 8 now. Its now really thick waist length . I use whatever good quality shampoo/conditioner I can find thats on offer. At the moment its the Aussie long hair version. Makes her hair a bit dull looking but it does keep it fairly untangled. I also use boots cheap and cheerful leave in conditioner after every wash which does make a big difference to tangles. Every night I loosely plait her hair else it takes 3 times as long to brush in the morning.