Paying the Google Tax
When I originally researched the mobile OS field for a 50-user project a couple years ago, we were considering ChromeBooks because of their attractive price point. We then discovered that enrollment in our MDM was going to require a certificate from Google's portal - at $199 a pop, that put the platform out of the running.
While the current state of affairs is an improvement, you're still going to pay the Google Tax. Any centralized management of ChromeOS currently seems to require an Apps for Work account, at $5-10 per user/year, depending on storage requirements - fine for a business that uses Google Docs for everything, but overkill for places that use SaaS elsewhere and just want a front-end device.