Steve,
This has been discussed at length here, so i'll try ro give you a summary.
Firstly with a midi router (Patchbay, Pipe, etc.), it's possible to wire Sibelius into Logic. Downside is Logic doesn't recognise articulation changes or expression markings on the score. (At least, that was the last update.) It's possible to hide program changes in Sibelius, but you can't switch channels per stave.
I use two scores. A working one, in which i set each articulation as a stave, e'g' 1st Violins sustain, 1st Violins Pizz,etc. if i want to use samples, and the usual conductors score. They bear little resemblance to each other, and if you use a working score first, obviously you have some changes to make converting it to a conductors score.
I've been experimenting with an AU host, and VSamp for playback, but of course you miss out on the other stuff in logic, and you can't record unless you add a further program specifically for this. The latest version of Sib (4) adds video, but little else, and if you visit their forum, you'll understand many Sib owners are dissatisfied with being charged for what is basically bug fixes, and a paltry collection of new features for notators like us.
So, my experience of Finale was horrible, Sibelius lacks VST hosting, and a means to playback in another program (Logic) without problems. With Sibelius you get Kontakt silver, an extremely limited range of poor samples, at least, that's my opinion. (No additional articulations)
You can of course write in Sibelius, then export the midi file to Logic, but you still have a mountain of work to do, to get decent playback.
I suggest you check out a program called Overture by Geniesoft. Overture 4 is due out tomorrow, and a demo (according to the owners) will be posted on their site tomorrow. OV4 has full VST hosting, and a pile of other features. I've been testing version 3, and although the screen isn't as pretty as Sibelius, it's actually easier to use, and the MIDI is stable, unlike Finale.
Logic has it's own score editor, but the impression i get is, it's insufficient for your needs. (As it is for many of us who like to watch notes!)
Best of luck, and you're not on your own. The day Logic and Cubase update the useability of their score formats is the day we may finally get something we can work with.
Regards,
Alex.
[i:d09f9c4039][color=blue:d09f9c4039][size=11:d09f9c4039]Orchestration is the art of making your own choice.....
Genius is the art of making the right choice....[/size:d09f9c4039][/color:d09f9c4039][/i:d09f9c4039]