The original Cinestar 8 three leg landing gear/camera gimbal system was designed to work with the MR in the "I" configuration for some reason and would not mount to the MR correctly in the "V" configuration. But now with the newer 3 axis BGC systems you can configure the MR to allow straight forward camera positioning in both "I" and "V" configuration.
Technically the "V" configuration is easier to fly for smoother aerial video work. This is based on a concept I learned and was able to verify when learning to fly the Blade MQX quad. It all comes back to a basic Archimedes lever principle, i.e., RC joystick control is a bit easier when flying the Blade MQX in the "I" or "+" configuration versus "V" or "X" configuration. its all about the real versus apparent motor arm length. The apparent motor arm length applies to the V or X config which is shorter. And a shorter motor arm length enables much faster response to joystick control etc.