I use a 3-9x40mm on mine. I hunt with it on the lowest setting, but due to antler restrictions where I hunt, it is nice to be able to increase the scope power to count points.
If you want to put a scope on it I would suggest a 1.5 - 5 X or something similar in power. I used to have a scope on mine but took it off and am going to install a peep on it.