Yeah, I forgot to mention that the Optimate 4 uses High Voltage/Low Current Desulfation process for heavily sulfated batteries which don't take charge. I would take my battery out for that process. The CTEK and BatteryMinder use pulses instead of high voltage. I'm leaning toward the BatteryMinder Plus for my Prius.
Going with Toyota OEM batt. It's $113 out the door at my local dealer after coupon. I was wondering if a battery that doesn't meet the Amp/hour rating of the OEM would affect my HV battery warranty. Honda apparently has a requirement for their HCHII.