The main difference between a standard Sprinkler System and a Water Mist system is the amount of water produced. Water damage can be worse then fire damage to certain properties so a Water Mist system can be the preferred option.
Depending on the circumstances, some insurance companies will only accept Sprinkler Systems where the Contractor can produce a LPS 1048 Certificate where a Misting Installation will not provide this.
The benefits of a Water Mist system are as follows:
Reduced amount of water required to control a fire.
Reduced plant space for pump and tank.
Reduced pipe sizes throughout the building.
The benefits of a Sprinkler System:
A LPS 1048 Certificate of compliance is produced.
BS EN 12845 is much more onerous and explains in detail about how the design should be.