You will get about 10 mpg (or less) pulling the Roo. The HW296 is a beast of a camper, but you'll get better mileage with it.
How far do you plan to tow and what weather will you camp in?
Set up is a lot easier with the Roo, but the HW will gie a much more "open" feeling. We camp in 5 degrees F in winter, and realize that the inside of our trailer isn't going to be anywhere near 67 degrees, so it's fine.
Have you been inside each one? They are VERY different.
Check them out and go with the one your better half likes.
Happy wife = happy life!