I'm running a hosting business here in Switzerland, mainly Windows based. However, we have been starting roughly 2 years ago to run more and more services on CentOS in order to overcome many short comings with Microsoft. Started off with ClearOS, but haven't been to happy with it. Now we are running Zarafa Groupware for our customers and are running it also internally. While I'm quite happy to usually start off with a CentOS minimal install when creating a new machine, it's a brilliant "something in between" to have Nethserver on top of plain CentOS. Provides our Windows geeks here a neat gui for the everyday stuff, while still building on stock CentOS. Way to go and extremely well implemented!