There are so many choices it can be confussing. And when we get into the showroom and don't know what we want, we can fall for the sales pitch. So first, define exactly what she wants. And what features she wants. Then look them up on the internet to see which models will fill those "wants".
I'm in the market for a machine and definitely want the button hole stitch. Finally had to ask the dealer for the specifics between 2 models, that made the difference.
So first define her needs. Then decide the priority of those needs and how much each is worth: $25 or $250 or $2500 to get a specific function.
A competent local rep is very important. I'm talking training, trouble shooting and service, not salesman persuasive.
I teach classes at a local Bernina dealer. I don't pretend to be able to trouble shoot (my function is to teach quilting). The store has employees who step in whenever someone is having trouble with their machine. The student gets hands on help with their individual machine (even non-Bernina if they can) and is more equiped to trouble shoot for themselves.
Besides a Bernina, I also have a Brother se1500 I bought in Sacramento,that has been great for about 15 yrs. Years went by with several dealers opening and closing. Took it in for service and got a promise of 1 wk, which he denied saying he never promises (that's a hint of his reliability). Two months later it came back with an advertising 4x4" sticker on the back-how pretensious. No way was I advertising for that store. Had to really work to get that sticker off. That dealer folded-wonder why? Anyway, check out the dealer.
Ask local quilters what they have and why. This takes time, not like buying a pair of pants. You get 1 machine but you buy several pants each year. Even going on a retreat with local quilters and check out their machines, it's very enlightening.
Good luck and have fun.