I use a mix of water brick and a 5 gallon water cooler jug as water storage for winter camping. I keep the Jugs wrapped in a blanket in the trailer, yet they regularly freeze. Each night, I top off the water brick and stash it in my Jeep wrapped in a blanket. Only had one morning with a thin layer of ice. This allows me to make coffee as soon as I get up.
The solution for the frozen water jug, as long as it isn't a full jug, is to put it on the top of the Jeep hood while the Jeep is running.
In general I find the water bricks easier to move around, and as they are only 3.5 gallons, my daughters can move them around. A full 5 gallon jug seems to be too big and/or heavy.
As time goes by, I'll probably continue to buy additional water bricks.
The spigot they sell works well as long as you place something under the back of the brick to keep the water level high near the spigot.