I use Finale 09 and love it. Its a great tool. However, it can be very limiting. Even though you can do almost anything with the program, some options are not readily available and you have to be a wiz at the computer to get every possible sound you want out of the program. I find that, if i usually write all of my music, first by playing it on either guitar, piano, or percussion. I find all of my main themes by playing them. Then i sit and write into the program and refuse to settle for anything less than what is in my mind. If it takes me a half hour to get a sound, i work to get it as opposed to settling for something less expressive.
Writing by hand is FAR better for growing in composition and for better expressing your thoughts but i am often too impatient for pencil and paper. I use them when im in class or anywhere away from my computer. I am a much faster clicker than i am a writer.