I’m considering buying a 2007 Saab 9-3.
Consumer Reports rates it as good, except for electrical problems. Do these tend to be major problems or minor annoyances?
Yes.
The car may have a very common problem with known (easy) fix that falls into the electrical category. Alternatively it could be many random things and annoying/major. Go to a forum specific to Saab and see what is up.
If the rest of vehicle is fine and you like it go for it.
My brother owner owns a 2003 Saab 95 Aero and absolutely loves it. Not a single electrical nag and very minor problems. He bought off lease for $14k with 42k miles but had minor body work in door(poorly done) that did not allow it be sold by Saab dealer as certified.