Both are Heavy themed decks that they try to recreate the story while you play them.
The Gondorian deck is meant to be the Resource engine of the fellowship, we use Mablung ability, Steward of Gondor and Horn of Gondor to generate lots of resources.
The Envoy of Pelargir and Pelargir Ship Captain provide resources to the Eorlingan side using the old marine routes and the Errand-rider ride through the battlefield to give Rohan vital information.
We have really powerful allies that can slay any foe we meet in game, Knight of the White Tower and Veteran of Osgiliath are the perfect target for Raiment of War with Boromir ability, and with Visionary Leadership they end being outstanding travelers if needed.
We got aswell, well-known gondorian defensive tactics with Gondorian Shield, Captain of Gondor and Honour Guard, which make our Heroes almost untouchable.
The Eorlingan deck is meant to be the Traveler and Support of the alliance. We got powerful questers like Escort from Edoras and Éomund. We also provide all mounts for the battle, Armored Destrier, Firefoot, Snowmane, Rohan Warhorse and Steed of the Mark with Elfhelm passive abilities will provide all kind of bonuses to our Heroes. The Westfold Horse-breeder will do their best to find the matching steeds in the stables.
Gamling is the main tactician of this deck, we can build really nice little combos with Westfold Horse-Breaker, Grimbold and Escort from Edoras giving us the chance to play them many times if needed. We also provide resources for Horn of Gondor in the Gondorian deck.
I really wish you try them out, they are really thematic for those who love lore and really powerful ingame.