I have sewn on many brands of machines over the years. Several years ago bought a Viking Designer 1. It will sew anything I put in front of it, even heavy denim with ease. It has a huge selection of utility as well as decorative stitches & does beautiful embroidery designs. It is heavy, does not vibrate the surface it is on like many can. It has yet to need any sort of repair at all. They are really made well.
I do agree with others here, you really need sit down & test drive a few at a time & think about what you would like to be able to sew.
My daughter is learning how to sew & there was no way I wanted her using my baby. So after doing a fair amount of reading on here for a decent budget machine I went got her a Brother CS600i Computerized Sewing Machine. I was really amazed at how well the little thing runs. It is a great starter machine.
I hope you & your wife will enjoy the adventure to find the perfect machine.