I have Notion. I am an amateur composer. It works for me if I compose in a classical style, for orchestra or small groups of strings, winds, etc.
I think it's strengths are it's palette of instruments from the LSO, easy to learn programming, and especially for me, that there's no need to use any other software. Instant playback and easy editing of notes. And it prints the score and parts. It feels like it was made for a composer to write stuff and then pass out the parts to his players, not so much to produce shimmering end-products.
It makes me really dig into things like articulations, rythmic figures, dynamics, on a note by note basis to amke it sound real. For me, I have to learn wht exactly "semi-marcato" bowing sounds like before i can use it, for example. It makesw me be a better musician in many ways. I've heard some great end products but that's not my interest as much as simple composing. For the big film score, you'll probably still want that sampler and orch libraries, gpo etc.