I think you have made a good decision in letting your wife in on selecting her sewing machine. I want to share my experience with you, just in case the information is helpful. My husband has got me sewing machines twice for Christmas. Each time he took me to a sewing store and let me try out machines. (It can be a very individual thing. Some might seem loud, might seem difficult to load the bobbin, etc....) Then he purchased the machine and I didn't see it again until Christmas morning. It worked very well for us.
I used the first machine 40 years, when I was sewing clothes, and the second machine has been mine for three years...the same number of years I have been a quilter.
You are one jewel of a husband, by the way, and your wife is going to love however you end up getting her a machine.
Dina