I've been poking around in the same area looking for a midi to notation converter.
I tried to use MuseScore to import a midi file I exported from iRealB to get the notation to see why that algorithmic 'player' sounded as good as it did.
MuseScore threw an exception when I tried to open that iRealB file.
I checked that the file was good by loading it in some home studio software.
Right now I have a 30 free trial of Notation Musician
http://www.notation.com/Download.htm
that does a nice clean job of converting midi files from iRealB and offers a bunch of other features including the ability to determine the chords being played based on piano right and/or left and bass part and place them on the score.
I'll probably be buying this soon -- $38.99.
There's a Composer product as well that allows editing, rather than just rendering -- which is more 87.99
From what I gather Midi Illustrator is also an inexpensive alternative.
These are the low end of the continuum that extends up to Sibelius. You can imagine the features and subtleties for notation software expand rather quickly.
If MuseScore works for what you want, it's hard to beat free.
