Best thing about Generals + Zero hour is the stuffton amount of great mods for it.
Here are a few Zero hour mods I recommend
Cold war crCIA - A more realistic total conversion mod set during the Cold war. Extremly realistic and hard compared to other mods and vanilla. All the models of the new units are full of detail and well done. The AI is certainly more challenging - even on "easy" setting. Factions are USSR and USA and both are pretty balanced - USA has air superitory while USSR has better tanks. Standard ressource gathering and Energy get replaced with supply flags which you have to capture with infantry and capturable / buildable fuel plants which you need to power your vehicles - it works just like the standard power system , just with vehicles. Infanty also becomes much more useful.
Rise of the reds - An amazing mod that adds more units , new models , sounds , buildings and a completly new faction the game - Russia.
The mod adds some features like a new scouting system , some amphibious vehicles and Tech structures , which you have to build in order to access more units.
All the units - old and new ones - were amazingly balanced out aswell. A lot of units got a new model aswell.
TIberian Dawn Redux - Another total conversation mod that now brings Tiberian dawn into CNC Generals.
All units and factions from the original Tiberian dawn are present but there are also 2 new factions and other units. Stuff like a working conyard , tiberium and walls. WALLS. Everything behaves a bit different but overall it's still nicely done.
They even remade a few campaign missions from Tiberian dawn and it's addon !
