The conversion to MIDI is quite good. This may change with the advent of tclabc . But it's certainly a step in the right direction. I'm expecting my next project to use a translator from ABC to one of the less typeable but notationally more complete formats. So it's likely that you will need some help getting started, or when you try new things.
Most programs have mailing lists.
The major reason I ended up using ABC was probably how friendly and interested the people on the abcusers mailing list were. The lilypond and musixTeX mailing lists are also quite good. An advantage of a text-based music publishing system is that it's easy to see what someone actually did to put the music in. All these programs have websites with lots of examples. For Lilypond, look at the short examples and The Mutopia Project .