I've been using Sibelius since version 6 (which is a long time ago) so I'm used to it. It's very powerful and produces great looking scores.
For the last couple of years I'd been using the reduced-feature set of the Artist edition; but a couple of missing features became ever more vital. So I bought the Ultimate version. It was wonderful to get back features I'd been missing since version 7.
You've got a choice of about 3 scoring programs: Sibelius, Dorico or Finale. Dorico is a newcomer and I don't know it; however, it was written with the help of some ex-Sibelius programmers. Of the arrangers I've spoken to, a slight majority prefer Sibelius.
So why not full marks. although it's very powerful and feature rich, it's also old and it's user interface is quirky to say the least. But if you're willing to get to know it, it's what I'd recommend.