I do not have a long arm, but I sometimes help my sister who has one. There is a lot more work involved than I would have ever dreamed. There are so many different things that can go wrong. If I were you, I would do as others have suggested....try one out. Take classes or rent time or find some way to get really familiar with one before you buy. My sister bought hers used, and not locally, and there isn't anyone nearby who services it or knows how to fix it if it has a problem, so she has had to figure it out herself. I would hate to have anyone else get a machine and not have some sort of local support.
Dina