If you play against the AI, at a certain point it will offer a surrender, say GG, and you can either accept or decline. When this happens, there is still a number of buildings (and possibly units) left to defeat. Destroying them gives XP, which will help me level, but if I accept the defeat, then I won't be able to destroy these units. Does accepting a surrender give me any XP? If so, is it more, less, or equal to defeating the rest of the remaining units/buildings?
Accept Surrenders ASAP!
When the enemy AI surrenders (the moment you accept it), you get XP for every unit the AI has that would reward XP.
The problem is, these popups are usually hidden by the victory screen itself.
So as soon as you receive the surrender offer, you should accept it, as it gives you exactly the amount of XP you would get from destroying all the remaining units / buildings.