Sibelius v. Encore v. Finale will always come down to personal preference. If you've used Finale since version 1.0 (like me), Sibelius and Encore will never cut it. If you work with the music publishing industry (like me), you'll find Finale has a much stronger hold than the other two (though that's always dependant on the kind of publishing you're doing). If you work with complicated scores or need the expandability of writing plug-ins to help automate tedious things or simply need your application to allow you the detail-tweaking that music publishing standards require, you'll find that Sibelius falls extremely short. At least, I did.
To me, it's like saying, "Yeah, I could use Photoshop, but I'd rather just use MacPaint. It's so much easier." You're missing the boat, and those of us who make money creating printed music for people who don't know how to use Finale are happy to see you go. We'll be sending you a bill soon enough.
Sibelius Version 2 is better than 1.4, but it still ain't Finale. I'll take a slow upgrade time over a new program that doesn't do half of the things its marketing claims it will do any day. And that's still just an opinion.
If it lets you do what you want to do, you've found the software you want. If that's Finale, settle in, because you're in for years of waiting for upgrades without the slightest clue what's coming next until it's time to buy it. Almost without exception, I've been utterly pleased with what came next.