Dear Arabei
VRV system is not intended for high ambiant climates such as in the gulf areas, and for quite place such as hotels and hospitals, it needs a separate leak detection system and fresh are ducting in all cases. Furthermore, supply/return ducting network is still needed if you chose to install the concealed type indoor units.
You need to stick to their control system, and their are many limitations on the selection regarding the minimum/maximum indoor units you can connect to the outdoor unit. Further, you cannot make any alteration to the system in terms of adding any accessories, guages, valves, regulators or extra refregerant circuits.
The last note, and in low humidity areas, and due to the fact that the system is designed to work at a refrigerant degree of 5.5 C, you need to add humidifiers to your space.
I recently heard that it was replaced in WTC-makka because of some of above considerations.
All the best