Dwarves in Pathfinder are known for being gruff and stoic, living in underground cities in the mountains, constantly warring with giants, orcs and goblinoids.
Ability Scores: +2 Wisdom and Constitution, -2 Charisma - this makes them perfect candidates for Clerics, Rangers, and Inquisitors, but hurts their chances of making good Bards, Paladins, Sorcerers, Oracles and Summoners.
Size: Medium - Dwarves don’t make very good sneaky characters, but otherwise their size doesn’t affect them.
Speed: 20 ft - Dwarves don’t move as quickly as other Medium-sized creatures, but this is made up for by their stoutness, which allows them to keep that 20-foot movement speed no matter what their encumbrance or what type of armor they wear. This makes them excellent candidates for any class that can wear heavy armor.
Defensive Training: A +4 dodge bonus to AC is nice, but it’s very situational because it only works against creatures of the giant subtype. If your character is planning to fight a lot of giants, dwarves are an awesome choice!
Hardy: A +2 bonus on saving throws against all spells and spell-like abilities is a pretty amazing boost, and it helps against poisons too, so this one is good for any character ever.