  We outline a general method for obtaining exact solutions of Schr\"{o}dinger
equations with a position dependent effective mass and compare the results with
those obtained within the frame of supersymmetric quantum theory. We observe
that the distinct effective mass Hamiltonians proposed in the literature in
fact describe exactly equivalent systems having identical spectra and wave
functions as far as exact solvability is concerned. This observation clarifies
the Hamiltonian dependence of the band-offset ratio for quantum wells.
