I wrote in the other section. You give up some light transmission when you put the laser safe coatings on to combo the rangefinder/binocular...even the high dollar German combo ones are not as good as their comparable straight binoculars.
On the other hand, I have enough stuff on my belt, the backpack waist strap can't take any more...So my rangefinder usually stays in the truck or in my pack...and not ready for quick use. The combo eliminates that.
Since I carry a small spotter anyway (I'll leave the rangefinder in the truck when paring down way before the spotter/tripod), I feel that the combo binocular/rangefinder is the way to go, used the Fusion's this year, and they are good enough optically for me, a better comprimise than the rangefinder in the truck
I still picked up more deer first, and don't think the light loss would make more than a minute or two difference in hunting time...
As long as you realize it's all about tradeoffs, you will be happy with the Fusion, it is the best value by far. And they are rugged...