Google Apps for sure
After using both tools, I would use this analogy, Google gives you a basic toolkit (hammer, pliers, screwdriver, wrench) Enough to get the job done, intuitive, fast, works well on multiple devices. A broad range of tools that work quite well. Microsoft gives you the 349 piece toolkit, Way more than most people need and you will need an instruction manual to figure out how to use all of the tools. They work pretty well on the Computer, but not so on other devices and the integration between client and web versions is poor. Considering the additional cost of O365, the additional support that is required, and the additional confusion, Google is the clear winner.