The system for me is always Raspbian, as I'm not good with Linux, so the Raspbian is rather comfortable version for "Windows XP people" like me.
As for the utilities, if You don't mind I will use fragment from another forum -
I use the MilkyTracker editor with the RPi2 computer (and lately also with the RPi 3).
Instruments have to be prepared earlier, on another computer (PC? Mac?) or have to be downloaded from some sample-collections, but entire composing process can be easily done on the RPi.
And again - for the newest Raspbian system in the Raspberry Pi 3 downloading and installing would be like this:
Preferences / Add - Remove Software / now search for "milky" word and install the program.
For the Pi 2 and old Raspbian - there is a problem as those %$#*^%$#* closed the Pi Shop (or however it was called back then, I can't remember now).
My friend from Atari 8bit scene - thePink - says that instead one should use the "apt get" command or something like that.
As for the samples, my favourite portal was the Music Radar:http://www.musicradar.com/news/tech/fre ... tis-627820
I suspect the Milky should also work on The RPi 1 (even if with small number of channels) and I think it must work on RPi Zero too.
And the prog in version of RPi looks like this: