We have used Google Apps for Education for over 7 years. We find ourselves constantly justifying the use of the service usually to Microsoftys. I personally do not believe that Google are doing anything untoward in the Education market in fact I think the complete opposite.
A lot of the blog posts you read are made as marketing ploys to try and belittle Google and big up the competitors!
See the following points from Google for Education
Gmail scans and indexes email for multiple purposes, including spell check, virus and spam protection, features like Priority Inbox and auto-detection of calendar events, relevant search results and advertising; this scanning is done on all incoming emails, is 100% automated and can’t be turned off.
When ads in Gmail are turned off for Google Apps for Education, automated scanning that is done in Gmail is not used to target ads to Education users, whether inside Gmail or in other Google products (e.g. YouTube, Google Search, etc.).
We do not scan information stored in Google Drive or Docs (or Sheets, Slides, Drawings, Forms) to target ads to Apps for Education customers.