With so many make ups on both females I couldn't really tell who is prettier but I think they both are. Honestly I do not know why people do so much to make them "look good" or something because I think to be attractive for anyone (guys/men and girls/woman) is to just be themselves without doing so much to try to be attractive if you see what I mean.
Emma Stone is prettier for me. in my opinion Emma Watson is just ordinary but i find kristin stewart so attractive. maybe kristin stewart is irrelevant to this question buıt i just wanted to write my feelings. :P
Emma Stone is probably my favourite current actress (along with Chloe Moretz), but it's not because of her looks. Still, she's certainly a lot more attractive than Emma Watson, who really isn't anything special.
I think Emma Watson is prettier. They're both pretty, it's just that I like her eyebrows and eyes more. They're not as sharp and cat-like as Emma Stone's. They make her look cuter and prettier, whereas Emma Stone looks more mature/sexy because of her sharp eyes.