hi,
Its very difficult to tell which coordinates is best...But many of the analysis can be done using cartesian coordinate system and its the fundamental coordinate system that is taught first than others so its best according to me...
happy learning....
it is based on the symmetry of the object considered, rectangular is better for all objects for objects with three dimensional symmetry spherical is better and for objects with radial symmetry cylindrical is the best ( it leads to easy integration)
It depends on your needs in the problem that you are trying to solve, sometimes you need the cartisan, other cylindrical times and other spherical times