I always take pictures with people, it makes the pictures more personal to me and helps me strike up a conversation with someone who's costume I like.
My friend once said though "Why do you always have to take pictures with people? it just annoys them and they think it's weird, I can see it on their faces when you ask" which I personally think is a load of crap, since everyone I've ever asked has been super nice about it.
Working on:Raffaele Laurent Bessette-The Young Elites, Shuu Iwamine-Hatoful Boyfriend, Oswald Baskerville-Pandora Hearts, Kirara Amanogawa-Go! Princess Precure, Grell Sutcliff-Kuroshitsuji (revamp), Sorath-Demon from Afar, Honoka Kousaka-Love Live! Gilbert Nightray-Pandora Hearts, Kitty Pryde as Star Lord-Marvel Comics, Surprise Halloween costume,