Thank you!
I know and use already Musescore to write my music. I think from the v.2 has became really really good to write music scores and MIDI as well.
Musescore and the Musescore Score Book have also all the playback features that I would look for, but in a really un-accessible in the situation of practicing music with an instrument.
(I mean: changing loop starting and ending point, speed of execution, mixer of the parts schould be at one-click-distance, specially in the mobile app).