Sibelius is the best for me- although I do not use it as a composition tool; cos that's bad- purely for playback purposes....
I've never used finale but havent heard much good about it to be honest from people that have.... however, I guess it depends on what genre you use it for and what your preferences are.... (I know Sib is expensive, but if you hunt around in the right places, and I don't want to encourage anyone here..... but you'll find cracked copies about.... Mine isn't cracked though, before you ask!!
)
However, as far as notation goes, you cannot beat Lilypond for it's engraving. Free program... amazing results.... I'm currently retypesetting all my publications to Lilypond format, which despight it's going to take a bit of time, it's
very much worth the hard work and effort, which is worth it seeing as it's all published music.
If you're not sure what program out of Sib or Finale is best for you though, download demos from the websites and try them out first.... then if you decide to purchase you're not going into the 'unknown' and won't regret wasting your money....
All the best!