I've ran goldfinger and snowbungee. I prefer the snowbungee. It sets away from the bars farther and is about four times longer than goldfinger and twice as long as lefties. The spacing away from the bars is what I like for a wider range of throttle input, and when you don't need it, it gives your gloves plenty of room on the bars for maneuvers.
That all being said, I rode a 2013 pro this weekend with no left hand throttle. I've been using them for ten years and was forced to learn how to ride like the next level riding clinics teach: opposite leg forward, never let go of the bars. I've always rode snowmobiles like my stand up jet ski, I use my rear leg to kick out the rear of the sled to help make the turn. Now without a lefty, I have to hop over the seat with one leg supporting all my weight (quickly, or you just turn back down the hill).
After the test ride with the polaris techs, I disconnected the snowbungee on my 12 pro and rode like the younger kids the next four days with the new riding style. I turn a lot faster now without the lefty and have been able to turn back up on steeper stuff than I was able to before. Problem is that one leg jump over thing. I'm 6'4" 250lbs and it ain't all muscle. I got tuckered out quicker with this kind of riding style, but it was fun, and it lets you go anywhere. Time to hit the squat machine this week or quit wearing a backpack while riding.