Each troop type has different attack and defense strengths, different size for transport and different maintenance levels. Each can be upgraded through their unique branch in the new ground combat tech tree.
Note also the troop types with green backgrounds in the planet details, these are garrisoned. You can have the automation set garrison levels automatically. You can also set them manually. Garrisoned troops will never be loaded by transports and removed from the planet, they stay and defend it.

















