Having one of the newer units that only has exhaust on both front and back, I can tell you first hand that having the front one on with the back simply open will in fact work wonders. On really warm evenings, I had the back one on low and the front one on medium and high with the windows open.
Not a great deal of noise, but it did create one heck of a breeze.
Personally, I love our Fantastic Fans. Particularly when they were open and running during the day, and a sudden storm would develop on us while I was out working in the field, too far to get to it in time. I never had to worry....those vents closed automatically and didn't allow any rain to get in. When dry, the vents opened automatically to and resumed full operation.
The word Fantastic doesn't even do them justice in my book.