We have a 2007 Dynamax 350 Grans Sport with Cat 350hp C-7 motor . The Dynamax runs great gets about 10 to 12 mpg depending where your driving. We tow a 2011 Honda Element and you don't even know it's behind you. I don't know about Forest River but I can tell you the Dynamax is a great coach and the fit and finish is great. When I call and talk to Forest River they are always helpful. I don't care what you buy you will always have some issues here and there.
Drive the Dynamax and make sure your wife drives it too I think you will like it.