I use Genisoy. I can't promise that there's 'no' grit, but it is the most palatable out of all the others I've tried.
Mostly, I mix it with almond milk and half of a banana. Cannot do without the banana. Seems to make all the difference. Takes away the 'soy' taste. I think the soy taste bothers me more than the grit.
Chocolate is my fav but I also like the vanilla and strawberry. Sometimes I use chocolate soy milk instead of almond and also add a tablespoon of peanut butter for an extra kick of protein (and calories when I can afford it, lol).