I'm almost certain that most times you see a usage figure of 9.5 to 10.5 hours, the phone played music either through its iPod/speakers/earphone function or BT streaming, with the screen off.
Hell, I can get a 10.5 hour use stat if 2 hours throughout the day was music.
But realistically, you can expect 6-8 hours actual use, closer to 6 with more cellular use, closer to 8 with more wifi.
The point is, take the 10+ use claims with a grain if salt, it's very likely they were doing something that artificially inflates usage times like music or certain apps that operate with very low power consumption. I'm betting a good average use time with no music is about 7.5 hours, which frankly, is pretty great for such a fast and powerful phone.