That was the basis of a recent evaluation report carried out by the Radicati Group.
From what I gather the Radicati Group carries out research on messaging and collaboration, security, emailing and many other web based services, so is probably a useful organisation to provide an unbiased view of Google and Microsoft’s Office 365 services. Therefore, I have to say the report the company compiled is quite comprehensive.
For instance, it compiles the evaluation into ten different categories. These are: administration, accessibility, cloud infrastructure, communication services, content services, migration and customer support, security, third-party support, mobile services and pricing.
The organisation also provides useful information about revenue forecasts that Google and Microsoft could potentially receive. Along with other cloud systems, the forecast for total revenue is expected to be around $6 billion by the end of 2016. The current forecast for the end of this year is $1.6 billion.
As for being the best, this information is something of a guarded secret and only available for those who are prepared to pay for the information in the evaluation report. Personally, given many companies switching to Google from their current systems, I would be very surprised if the report didn’t conclude that Google’s cloud system scored more highly that Microsoft’s Office 365 on most, if not all of the ten categories listed above.
Microsoft had hoped to compete with Google, but it seems the company has constantly struggled. In fact, losing its competitive edge recently forced the software giant to create a comedic video, attacking Google Apps.

The title is a bit of tease!
I agree with your conclusion though, just from anecdotal evidence that Google apps are the preferred option over Office 365. I would also be interested though to see what impact Open Office is making, I talked to a few very large companies that are moving to open office as their documents can be opened in Office and Google apps making easy to share files.