Some characteristics of reversible phase-change optical data storage in TeSeSb alloys are given. High signal-to-noise ratios are reached at low recording energies. Upon passage of an oblong scanning laser spot, erasure occurs by growth from the crystalline surroundings of the amorphous effects at growth velocities of up to 5 cm/s. Isothermal transformation appears to be dominated by phase separation and diffusion processes. The tradeoff between long-term stability and erasure time varies with alloy composition and, for some alloys, attractive properties with respect to data retention and erasure times are found.