Google maps is usually (but not always) accurate. On one occasion maps on my Android phone got the location of a hospital in Shanghai completely wrong. Baidu maps are usually more accurate and up to date. I have both installed on my phone.

As mentioned above, city8.com is a Chinese Streetview equivalent. Neither Google maps nor Baidu have this functionality for China.

kind of offtopic but the smartshanghai app is very helpful. it has a subway map and i THINK a map of the city as well.