The type of supercharger that is most efficient is the centrifugal supercharger. It is very reliable because it contains few moving parts. It is also small and can be placed almost anywhere within the air intake system. This type produces the lowest discharge temperature because it incorporates the use of venturi tubes to increase pressure. The only drawbacks are that it needs external lubrication, and it provides little to no boost at rpms below 3,000. Centrifugal superchargers require an oil line to be connected from the pan to the unit for lubrication. However, once this is accomplished, it is relatively maintenance free.
For more info, see Supercharger Tuning Made Easy