Re: Lack of integrated email/contacts/calendar?
"Just to note that Windows 8.1 outperformed the latest Ubuntu in benchmark tests such as boot time, 3D graphics and copying large files..."
That's great, and I tried Windows 8.1 - yes it's very quick to boot. So that's saved me about 12 seconds a day.
3D graphics? Wonderful but I don't care in an office environment.
Copying large files? Again (almost entirely) unnecessary in an office.
Having used Ubuntu for 2+ years for work and dual booting to Windows 7 on the same machine, I found little difference in program performance, but Ubuntu was generally quicker at drive access and more stable (particularly Firefox).
And I wish I'd had an Outlook equivalent. Though Thunderbird was good for most jobs.