The circulating heater helps more with keeping the oil warm than a freeze plug heater. A heating pad helps even more. However, a 5W20 oil flows very well at any temperature you are likely to encounter. A full synthetic 0W20 or 0W30 may flow even better.

 

I don't have a block heater but I do have a remote start. One of the best mods I ever did. It's nice to have the truck warm when it's 0 out, and makes getting ice off the windows a breeze.