Yes, it is recommended that each user has an individual Google account. Apps are not shared. You can change the user from the lock screen or from the right pulldown menu. A user can be created from menu > settings > users.
Thanks, I added a user with no trouble. Very easy to choose a user at the startup screen (after you give the owner and the user nicknames you will recognize -- this is done in the settings screen for Users). Each user has his/her own apps, but if the owner has an app, it does not appear that any additional storage space is taken up for the app itself when installed by the second user.
This is a fantastic addition in Android 4.2.