The reliably accurate solution of the Dirac equations even in the simplest molecular cases (two nuclei plus one electron) may pose severe problems: spurious solutions, contaminated states, non-convergence and spurious convergence. Only recently this has been understood as a principle problem of good solutions in approximate spaces and thus being basically an efficiency problem. Whereas non-relativisticly the best energy in a finite basis is obtained by variational minimization of the expectation value of the Hamiltonian under conservation of norm (Rayleigh quotien) this does not work in the relativistic case, because the Hamiltonian is unbound from both sides. A solution which eliminates all the above problems perfectly is minimization of a minimax functional. However this is generally very expensive to do, because it is non-linear in the eigenvalue. Therefore one searches for other yet sufficiently effective variational principles where the projection properties against spurious positronic contributions in electronic states are quite accurately incorporated. Thus one reaches almost the efficiency of the minimax functional, if one includes physical knowledge about the relativistic electronic system, yet avoids the strong non-linear energy dependence of a minimax functional.