I've been using Sibelius since 2003 (version 2). Don't feel bad if you can't pronounce the music publishing software named for the most famous Finnish composer of all time. It's si-BAY-lee-us. And it's a strange name for the software (not sure if Sibelius was famous for his notation), but I love it. I finally upgraded to Sibelius 5 this week and spent a little time exploring the new features; it's not new, but it's new to me. I'm torn. Some of the new features are great. For example, the "ideas" hub is really convenient. It's like a virtual notebook to store little musical snippets that composers collect. I like to carry a little notebook to write them down in. Now Sibelius will keep them for me. The mixer window is also new and improved with a cleaner look and more features (including some nice audio upgrades... though I don't really use Sibelius for its sounds, it's convenient to be able to quickly export an aif). Speaking of a cleaner look, I think the whole package looks cleaner--not dramatically different, but it's always fun to upgrade and feel like you've got something new. And it seems to run more efficiently on Mac OSX Leopard.
On the other hand, some of the new automations have gotten me down. The biggest reason I switched from the then-industry-standard Finale was Sibelius's manual, but intuitive feel. Finale is controlled by a complicated system of "tools" that try to streamline compositional inspiration into a finite set of possibilities. You're never sure how to manipulate the application into giving you exactly what you want using its automated controls.
With Sibelius, you have a blank slate with infinite possibilites. There has never been (until now) a "scroll view" in Sibelius--you look at virtual sheets of paper on the screen, and the art of formatting the score is left to your imagination. You can put notes, text, or graphics wherever you want. You can end staves, change transpositions of staves, and label staves manually. You can shrink notes to get cues and enlarge the fonts for every kind of text from dynamics to time signatures. I find it comforting to have so much control--it's like using a pencil and paper without the hassle. Isn't that what music notation software should be?
Sibelius 5.0 has several dubious "improvements." The scroll view is, at least, inelegant. Although it is not the default view, it panders to Finales users. Another nod to Finale's inelegance is the new automated cues. I don't want to have to remember a hundred automactic functions designed to help me. I simply want to shrink notes so that they look like cues. That's intuitive. The new "change instrument" feature bundles the old staff transposition with the corresponding instruments playback change. I prefer to make these changes manually. That way, I get exactly what I want--not Sibelius's best guess.
Overall, I like the changes in version 5, but I'm worried that some of those changes point toward more Finalification in the future.
*) Here is a sample of the playback sounds. It's an arrangement I did last fall of "Billie Jean."