I would say you will need to provide more training for Google Apps than for Office 365. People are more used to Office and Office 365's UI since they are similar compared to Google Apps where things are completely different. Also, nobody talks about Office Web Apps.

Google apps actually competes with Office Web apps technically speaking and Office 365 users have the option of desktop apps. Google Apps don't have a desktop companion.

Then add the rich feature set of Office products and Google Apps are dead meat.