For me, product buildup (which is generally from polyquats) makes my hair feel coated and it doesnt shine as much as if it were clean. The curls are limp and dont form properly, they look fuzzy. It just feels COATED if that makes sense. hehe.
Whereas with protein, it doesnt FEEL coated so much. Instead the hair is just incredibly dry even if youre using a moisturising conditioner (that contains proteins...) My curls still formed ok although there was more frizz, although it wasnt the fuzz i get with product buildup.
Product = lank, almost greasy, no texture.
Protein = straw-like dryness, frizz.
I have to clarify now and then if I'm using a cone that isn't water soluable or that easy one to remove. My hair bounces back like magic.
However I can't use the OO all the time without using Dt's to compensate for the proteins
so typical has happened to me many a time! i found this gorgeous leave in (charles worthington moisture seal) which actually lightened my blonde highlights as well as making my hair super soft and shiney, until two days after buying two bottles of it my hair was drying out like crazy. it has a whole lotta protein i HAVE found howver that if i use a protein free cream under a gel that has a small amount of protein i can do ok...
hope you find another conditioner that leaves you with soft hair!