It just so happens that I use both
Let's go into the details a bit.
Finale
Pros:
-Absolutely wonderful notation abilities that produce great looking sheet music with minimal effort. If you are willing to delve a little deeper, you can make some really complex sheet music.
-opens as a conductor's score but to create the individual parts, it takes 1 (yes that's right - 1) click from the file menu. Instrument parts are automatically formatted and made beautiful.
-comprehensive MIDI editing capabilities.
-just about all major instruments are represented in the setup wizard but if you need a staff for an obscure ethnic instrument (a Chinese Erhu for example), you can easily create a blank staff and format it yourself which takes only a minute.
-full support for AU and VST plugin sample libraries.
-ability to scan existing printed sheet music and import it into the application for playback and editing.
-ability to transcribe sheet music using real time performances with a MIDI controller (such as a MIDI piano).
Cons:
-more expensive
-no audio recording capabilities (only MIDI recording is accepted)
-unless you are willing to really tweak the MIDI data on each note (which can be time consuming), playback of your piece will sound very mechanical (like... well like a computer is playing it and not a human being).
-MIDI editing tools are not very streamlined. Be prepared to enter numeric values rather than seeing visual references.
Logic Pro
Pros
-Less expensive
-full featured DAW with full support for all major audio and MIDI interfaces
-comprehensive effects plugins such as reverb, compression, flangers, etc
-comes with a lot of loops and MIDI samples right out of the box
- it's sort of a "if you can imagine it, you can make it" program
Cons
-Logic can create sheet music too but it's a royal pain in the butt to create even halfway decent looking scores. All page formatting is on you to manually enter. Adding notes to the score is not nearly as easy as on Finale. Separating the parts is much more difficult.
-steep learning curve. Be prepared to go online for some educational courses.
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It boils down to this: Finale exists for one purpose: to make and print sheet music. Sure it does other things too (it can export your score as a MIDI file for example) but it's core function is the printing of music.
Logic exists as a DAW for audio recording. It does sheet music too but after getting used to Finale, Logic's score editor gave me a headache and took easily 5 to 10x longer to do. Even for simple scores.
Which matters more to you? I'm assuming that your school will have a recording studio and their computers also have Finale (or it's rival, Sibelius) so which would you rather be able to do at home as well?
Don't forget you can download a free trial of Finale 2012! I would take it for a spin if I were you.
Finale 2012 - The world standard for music notation software