we are/were 100% MS. But when the pricing news for 2016 first broke we decided to look elsewhere. Cloud is no use to us. This year we started transitioning away. First was the majority of non aspx web server. now we are migrating SQL.
Next will be email and once email has gone then Office goes too. we anticipate a single MS webserver for aspx. So from 10 datacentre, sql and exchange to 4x 2016 (twin host) std licenses.
full linux in 5 years desktop and backend. We wont be the only ones doing this.