Well.. back in *my* day

- I had a MS10. This was a bazzillion years ago. I used it for lead in a couple of songs (i was playing in a cover band at the time). It wasn't too difficult to learn/use - but I certainly would never had tried to create a full song with it. The iMS-20 is similar, in that I wouldn't try to create a complete song with it. It just isn't the right tool for the job.
What I like about GarageBand, is that I can quite easily pull together a full tune. The sounds are limited, and canned. The editing capabilities are crippled. Apple seems to be protecting their Mac market, and fuller featured editing software titles. They have given GarageBand enough capability to save off pretty good tunes though.