Maybe I'm missing something but isn't the installer for Debian usually smaller and more tuned for servers, and isn't this command line only version of Ubuntu basically the same as Debian? Why use Ubuntu for servers?
In my case because I use it on the desktop, I like it and I'm used to it. Ubuntu may well be similar to Debian, however I've never used Debian and I know Ubuntu is similar to Ubuntu.
> Surely for some applications Windows would be a good solution too?
No.
That's the old model, as of last week you should stop paying too much for your Operating System every couple of years and start paying too much every month to run you applications in the Azure Clouds.