My Setup

Compared to plugging it into Kontakt with some decent samples libraries loaded, the sounds in Sibelius aren't that great.

And yes, Sibelius is more about getting notes on the staves, but I like to have good play back whilst I'm composing, not just after I've finished a piece. At the moment Sibelius 5 is the piece of software which is best for me; the playback's not as good as in a sequencer but I'd rather compromise on the playback a bit to gain Sibelius' ease of input. If Sonar came up with a Sibelius-esque way of entering notes in staff-view I'd use that instead.

I want the best of both. And at the moment Sibelius 5, not Sonar is the closest to realising that.

well, obviously, the kontakt library adds another 2,5 gigs of space.

i compose pieces in cubase or protools cause they're so flexibel, and when there's a need to print scores, i'll use sibelius. i'm more used to working with sequencers, since i don't only compose, i also do mixes and whatnot in them, so i just know my way around.
still, i enjoy sibelius, though i'm not very efficient in it as i like to be .

to everyone his/her own approach.