I would recommend looking at what brands are available where she will be living so she can get service. Then maybe visiting the shops there so she can try them herself.
Sewing machines are very personal. Just like cars and brands of jeans. Some you hit it off with, others are frustrating, and everyone is different. Let her try several and see which "feel" more intuitive to operate. The more approachable/intuitive one's first machine is, the more likely you are to stick with the hobby.