Civ Bonuses:
+30% villager build speed. (except for wonders)
Blacksmith upgrades require no gold.
Cannonballs shot from Cannon Galleons move through the air faster and get balistics.
Team Bonus
+50% profit from trade.
Unique Unit:
Conquistador: It is a handcannoner mounted on a horse. It is more expensive then a handcannoner and has less range but it has more hit points, and speed. Cost is 60 food and 70 gold.
Missionary: It is a monk mounted on a horse. It is available at the monastery after a castle is build. It moves faster and has more hit points then a monk, but has shorter range and cannot pick up relics.
Unique Tech:
Supremacy: It gives villagers more life, armor, and attack power. They have stats similar to long swordsmen.
Tech Tree:
Have champions.
Have paladins.
Have all gunpowder units.
Have all infantry and cavalry blacksmith techs.
Have sappers.
NO crop rotation.
NO Crossbowmen.
NO siege engineers
No Camels.
Comments by AOK:TC deigners paraphrased by Cherub BroacLanders:
The spanish are a generalist civ. They have a good selection of units to use. Since their only economic upgrades are the trade bonus and no gold blacksmith techs they are very slow. They are the most vulnerable in the castle age because of their weak economy and lack of crossbowmen.

Spanish are similar to Turks. In imperial age they become extremely powerful. They have paladins and champions with cheap blacksmith upgrades and have all gunpowder units. Although the gold free blacksmith and increased trade profit helps them get gold, they are still very heavily gold dependent. Their paladins and both their UU's will cost you tons of gold. They are a powerful naval civ and have some of the best cannon galleys in the game.

Their main disadvantages are their weak early game economies, gold dependency, lack of archers, and weak siege weapons and lack of siege engineers.

Their main advantages are their powerful imperial selection of units, powerful navy, and increased trading ability. They are also the best forward builders in the game. Their super tough villagers with increased build speed, lets them plop down castles and other buildings in the heat of battle.

The best way to deal with the Spanish is to attack early and try to deprive them of gold.