The advantages of S.I. are as under :
(i) S.I. has broader base. It has seven base units and two supplementary units.
(ii) S.I. is rational, i.e., it gives one unit for one physical quantity, e.g., for energy of any type, i.e., mechanical or heat or electrical. There is only one unit, Joule (J) but in M.K.S. system unit for mechanical energy is Joule.
(iii) S.I. is coherent.
(iv) S.I. is metric.
(v) S.I. is the modernised and improved form of M.K.S. system so it is readily accepted in almost all the countries of the world.
(vi) The symbols fixed by S.I. are not subject to change
whatever may be the language, e.g., unit of mass kilogram having symbol 'kg' has to be written like this only in French or German or Hindi or Punjabi etc.