We just released VsysCalendar WP8 which fully supports Windows Phone 8 platform.
As new features in this version includes various live tile sizes, voice input, new local database, supports all resolutions.
VsysCalendar WP8 can be synced with both Google and Windows Live directly. And, allows you to full edit appointments.The calendar app offers three different calendar views, search functionality, multiple reminders and much more.
There is a 5-day trial version so you can test it thoroughly.
The app can be found in Marketplace here.