Google Calendar users with an iPad should check out the app of the week. CalenMob Pro has an uncluttered interface that syncs nicely with Google Calendar and makes it easy to keep up with multiple calendars.
In addition to syncing with Google Calendar when the app starts and events are changed, CalenMob Pro has an offline mode that works with Google Calendar without a web connection. Events can be changed and/or created offline and will automatically sync to Google Calendar when a connection is available. The app will also work with the iOS calendar.
CalenMob has all of the standard calendar views: day, week, month, year, and agenda. There is also a 4-day view which is particularly useful on the iPad and iPad mini.
Event entry is easy with the special entry controls in the app. It provides a simple tap interface for selecting the date and time for the appointment. Events can be assigned a contact from the Contacts app on iOS6.
CalenMob Pro is $6.99 which is a little expensive for a calendar app but is worth it for those with busy Google Calendars. It is one of the most-used apps on my iPad and iPad mini.