I've installed and used them on several different aircraft for various purposes (filming a documentary, experimental monitoring, etc). What you mount and how you mount it is best applied specifically to the aircraft in question. That is, what works on one airplane for one purpose isn't necessarily appropriate on another. Small changes to the external airflow can have pronounced effects on the operation of the airplane, to say nothing of flutter or other issues.
I've seen some gear mounted externally which appeared to be well engineered and stable, but which produced vibration or a buzz, or conditions I deemed unsafe, upon loading the wing in a turn or when maneuvering. Similiarly, what works in a clean configuration may not be acceptable in a landing configuration, etc.
Mounting a camera seems like a simple exercise, but it's a lot more than simply putting a fairing up and attaching a camera. Particularly if you'll be mounting it external to the pressure vessel, and trying to run it from inside the aircraft. Generally you'll need reinforcement under the surface where the camera is mounted, and you may require sealed wiring.
What application are you doing, here?