Well, you can blend between the two orientations. For example, your final orientation can be composed of 75% Intersense data and 25% Vicon data. However, you should be aware that the Intersense might accumulate some drift depending on your physical environment (metallic interference etc..). Here is some sample code that will accomplish this:
Code:
q1 = isenseOri.getQuat()
q2 = viconOri.getQuat()
# 'q' will contain quaternion rotation with 75% Intersense data and 25% Vicon data
q = vizmat.slerp(q1,q2,0.25)