I have a dual batt setup and was debating on getting an isolator. Is it really worth getting one? I tend to do a lot of parking with the radio on and tend to drain the house battery regularly.

The advantage of having the isolator is you charge both batteries at the same time whenever you are running. No need to remember to change the switch for charging. The drawback to the isolator setup is the voltage drop across the isolator rectifier means longer charge times for either battery.