Absorption of laser radiation in the optical element leads to depolarization resulting in limitation of isolation ratio. In order to suppress this self-induced depolarization two new optical designs were recently suggested. They utilize two 22.5 degree Faraday rotators and a half wave plate or reciprocal rotator between them. Both schemes allow an increase in isolation ratio at the same beam power. However all other parameters of the isolators were not investigated. All three designs are compared from the viewpoint of the first pass through the isolator. We derive equations for power losses, amplitude and phase distortions as a function of the laser beam power. Both crystal and glass magneto-optical media are investigated. It is shown that the scheme with reciprocal rotator is the best from the viewpoint of the first pass parameters as well as from the viewpoint of the isolation ratio. The results obtained for a Gaussian beam in the present and previous studies are generalized for the case of super Gaussian and flat intensity distribution as well. It is shown that the flat- shaped beam induces the weakest distortions and the Gaussian one induces the strongest ones.