The 560W Zeus is getting very popular very fast - it's an industrial grade server unit dressed up for the consumer market. Other similar units are the PC P&C 510W, and Zippy's new gaming units.
Of the models mentioned, the Fortron AX500-A is the least powerful and the Silverstone the most. Being OEM Etasis, the Silverstone also has a build quality advantage over both others. However, the OCZ is the tightest regulating.