  The magnetic-field, temperature, and angular dependence of the interlayer
magnetoresistance of two different quasi-two-dimensional (2D) organic
superconductors is reported. For $\kappa$-(BEDT-TTF)$_2$I$_3$ we find a
well-resolved peak in the angle-dependent magnetoresistance at $\Theta =
90^\circ$ (field parallel to the layers). This clear-cut proof for the coherent
nature of the interlayer transport is absent for
$\beta$''-(BEDT-TTF)$_2$SF$_5$CH$_2$CF$_2$SO$_3$. This and the non-metallic
behavior of the magnetoresistance suggest an incoherent quasiparticle motion
for the latter 2D metal.
