How many of you are using a UPS Back-UPS with Snow Leopard, 10.6.6? Is APC UPS Back-UPS ES 750 fully compatible with iMac using Snow Leopard 10.6.6? I am using the native Mac OS energy saver UPS in System Preferences to control the UPS, since APC doesn't offer software for OS X 10.6.6. Is your "time remaining" unsupported? Will the MAC OS actually shut down your computer according to your UPS settings in System Preferences? Finally is the ES 570 powerful enough for a 21.5" iMac?