CalenGoo vs Fantastical
CalenGoo gives you a fast and easy way to access and change your Google Calendar (or Google Apps Calendar) with your iPhone, iPod Touch or iPad. It even works when you have no internet connection. Changes are saved and uploaded the next time you are connected.
The Mac calendar you'll actually enjoy using. Fantastical's natural language engine is expressive and intelligent so you can write in your own style. Even better, Fantastical automatically recognizes the location of your event and can even invite people from Contacts (Mavericks and Mountain Lion) or Address Book (Lion and Snow Leopard) to your event.