Security: The algorithm uses eleven hashing functions from the Blake algorithm to the Keccak algorithm making it very secure which really is needed for coins that do so well for CPUs
Effectiveness: The X11 Algorithm gives amazingly fast hashes for both GPUs and CPUs. It also keeps GPUs over 30% cooler making your expensive graphic cards less prone to overheating. The reason? Graphic cards dont require as much processing power in order to mine the coins with this algorithm
Power Cost: Due to how effective it is, graphic cards do not require that much power in order to mine it. Therefore, you will see significantly lower electricity costs at the end of the month. This makes coins running this algorithm to be a favorite in places where electricity costs are far from bearable.
Mineability: Being more complicated than a SHA256 ASIC implementation, the use of X11 will prevent the use of ASIC miners in the short term to midterm future. It will also allow for a longer period of mining for CPU/GPU users.