It's a safe neighborhood. 100th and West End is actually a pretty quiet residential neighborhood (full of apartment buildings). One block over to the east is Broadway which is pretty lively (lots of shops). 16 blocks to the north is Columbia University's main campus.
It's kind of far from NYU though-- It'll take you at least an hour to get down there by subway, factoring in the walks-- You have to walk to 96th and Broadway to catch the subway, and after you get out at 23rd and Park you got to walk all the way to 24th and 1st.
HTH!