I shall address perturbative vacuum stability in the four available settings for the tachyon-free ten-dimensional strings with broken supersymmetry. The first two settings are families of AdS3 x S7 and AdS7 x S3 vacua, supported by form fluxes, with small world-sheet and string-loop corrections within wide ranges of parameters. The other settings are compactifications with nine-dimensional Poincaré symmetry and cosmological solutions where the "climbing" phenomenon takes place. I will also attempt to draw some general indications from the resulting behavior.
