Pros and Cons of Guard Mode

Could somebody tell me the pros and cons of Guard mode in Europa Barbarorum online? Thank you, any help is appreciated. :)

Well it makes it so you can conserve stamina and makes your units not run after other units. Its really good for fighting heavy infantry but kinda bad for fighting really light armored AP infantry.

Also, and seeing this in battle for yourself will explain better than I can, there is a difference between idle guard mode units and engaged guard mode units. By idle I do not mean not fighting and by engaged I do not mean having been attacked. Rather, by idle I mean the unit may be fighting another, but you did not order it to. And by engaged, I mean you ordered the unit to fight.

If I remember correctly, and logic would have it so, the idle unit will not kill as fast as the engaged unit, but will not lose stamina as fast either. On the other hand, the engaged unit will kill faster, but it will tire faster as well. I'm not sure if it will tire slower than a non-guard engaged unit, but I want to say they tire all the same. What really happens I believe is the unit 1) does not spread apart (break formation) and 2) it (usually) does not give chase upon enemy rout.