Marius

Sibelius is vastly less useful than Cubase as a sequencer, largely because it's not MEANT to be used as a sequencer.

Sibelius is fundamentally a piece of NOTATION software - it may start including features for basic sequencing, but it doesn't rival the capabilities of Cubase which is dedicated to sequencing.

There really isn't much of a comparison between the two because they're intended for entirely different things: Sibelius for notation, Cubase for sequencing.