I just installed the POWER-GATE Dual Rectfier on my wakeboarding boat. I have two batteries and had issues in the past with the Perfect Pass cruise control (very voltage sensitive). Previously, I had a standard battery isolator but the voltage drop was too high. My Perfect Pass would freak out when I turned the heater on and my amps weren't getting all the power I wanted them to get.
The POWER-GATE was the perfect solution. After checking the voltage at each connection, I find that I lose less than .05 volts through this device. Outstanding! Installation and connections were a breeze. Another neat feature is the battery combine feature. I used to carry jumper cables just in case I needed to jump-start the starter battery from the Aux battery. With POWER-GATE, I installed a momentary switch on my dashboard that combines the batteries briefly if I ever need to jump start the boat.
All in all, this is a more pricey device, but it is the very best. That's why I bought it and that's why you should buy it. No more worrying or electrical issues to deal with, just fun on the water :)