The game itself is pretty mediocre nowadays. Servers aren't that great, game has more or less became Pay to Win. I don't have a specific program I use for MML. Mabinogi just has an in game scroll item you can write MML in to play it. I do all these songs in Noteworthy Composer, then convert them to MML using a program called 3ML(an MML program that can convert MIDI files to MML, or can be used to manually write and test play MMLs).