I highly encourage high command

I recently started using high command, about a month ago, and what I've found is that the most powerful benefit is the ability to set artillery on what is called "aggressive". In aggressive mode artillery will march to within range of target, stop, then start firing at target. When they have killed target they will continue on their march. This is a really big advantage since you don't have to manually start and stop your units. Artillery are one of the best units in the game as they can take out the enemy with no losses. The high command option just makes them that much better. The aggressive mode also works on ships which is very useful. There is also a "hold fire" mode that makes subs very powerful at sneaking anywhere they want. There are several other significant benefits to high command I won't go into, but I will point out that later in the game it can be very useful to be able to queue units in newly acquired provinces close to the front line.