How much differences between Guardians Levels?

[FreeEagle]

I am new to 3 levels world and I am just wondering how much differences in percentages between each levels? Thanks

[MechaStorm]

There is a slight increase in the attack and defense statistics ik each increase of level

[Gionzau]

Check the units summary page. There's a decent increase when going to level 2, and only modest going to level 3.
Note that the level of a troop type in a city dictates the level of any support in the city, so sending your shiny level 3 guardians to a city with level 1 guardians means they'll perform at that level too.
Just make sure all or most cities are on level 2 guardians minimum