I drove the XG-350 (rental) on several business trips to the Washington DC area. I actually thought I was getting into a blend of Jaguar and Lincoln the first time I saw it. It wasn't until I was out of the dark parking garage that I realized my "up-grade" was a XG-350. After that I made it a point to drive them when I could. It's solid, smooth, and quiet at and above interstate speed limits. Truth is it will fly at relatively moderate RPM. At speed limit (65-70 mph) I get 32-33 MPH. Above speed limit 21-22 MPH is the norm. Its quietness will deceive you. Don't be surprised when you think you are doing 70 and its 85 or above. Love this car. It's a winner in all categories.
Sound of sturdy build "high-end" door shutting. Automatic seats, seat warmer, automatic air and entertainment center are just like its expensive cousins. Great feeling when you give it the gas, and so quiet at speed limit it makes you think you are well below the limit. Leather seats are great.
It's great as is, but a GPS package would be great. Also it would be helpful if the trip indicator monitored exact MPG to help with efficiency. Engineer the open sun roof to cut some of the wind noise. Larger Radius wheels.