The Essentio takes the, well, essential requirements for a pen, and adds very little. But this is Faber-Castell, so a bit of style and good looks is, of course, essential. But that's no bad thing. The resulting pens have strong metal clips, soft-touch grips, and simple good looks. The ballpoints are retractable, for quick and easy use. Simple, yes, but not too simple - the sort of design Germany does so well.
The Essentio used to be known as the Faber-Castell Basic - same great pen, just with a name that suits it a bit better.