The Dwarves are an ancient race with long memories. They fought against the coming of chaos before men were even organized into tribes. Although allied with the High Elves for a time, the Dark Elves engineered a war between Dwarves and Elves which resulted in a pyrrhic victory for the Dwarves. This was followed by a giant earthquake which devestated the Dwarven mountain holds, unleashing hordes of goblins and skaven into Dwarf lands. The dwarves make a point of holding grudges against all who have wronged them, writing these down in books to be repaid at a later date.
They maintain strong ties to the men of the Empire who helped them in the past, even though men barely remember this. They stand in conflict with Orcs, Goblins, and Skaven who have taken over much of their historical lands. And they maintain an uneasy truce with the elves, who they will not forgive for the war between the two races.
How much you enjoy painting a dwarf army depends on one thing: how do you feel about beards? The defining characteristic of all dwarf models, some love them, some hate them. A dwarf army has the potential to look fairly boring, being just variation on several short guys in shiny armor with beards. However, since dwarves are known not for fighting in a standing army with identical uniforms and equipment, but instead going to war with their own armor and family heirlooms, there is a great deal of potential for adding diversity to blocks of troops though conversions and a variety of color schemes.
While dwarven core troops are all in plastic, their elite infantry units are still metals. Also several of their war machines are still in metal as well. This can potentially drive up the cost of a heavy infantry dwarf army. But since dwarves share visual similarities between each other, conversions from standard plastic core dwarf warriors into elite hammerer and ironbreaker units are not too difficult.
A nice plastic lord/bsb kit exists, however all other characters are still in metal.
The ragtag nature of dwarven troops and technolgy, and usefulness of the core dwarf warrior body in modeling almost any dwarf makes them a very customizable army for somebody who is good with a razor blade.
Dwarves are some of the toughest troops in the whole of warhammer. The bog standard dwarf warrior is beat out only by a chaos warrior, and comes in at a much lower point cost. With leadership 9 across the board as well, dwarf warriors form a highly reliable wall of steel, even when far from the support of their general and bsb. Their warmachine crews, who benefit from stubborness, are capable of fighting off light cavalry assaults.
Where the dwarves differ from every other army is their lack of movement. With no cavalry and only a single rare flyer unit, your entire army is stuck at movement 3". This is somewhat offset since dwarves are allowed to march a full 6" even when in proximity of the enemy, making them immune to marchblocking. That said, the dwarven movement phase is still quite involved, focusing less on trying to get the charge, and more on controlling which one of your units the enemy will charge. This can cause difficulties for elite blocks of troops and expensive dwarven lords, as most enemies will try to avoid these blocks.
The other area in which Dwarves are unique is their use of runes. Instead of a list of magical items, dwarves have access to a massive variety of runes. Each piece of a character's equipment may be inscribed with up to 3 of these runes, resulting in an amazing amount of customizability. Dwarven warmachines and magical banners may also be runed.
Dwarves are the only race in warhammer to wholesale reject the notion of magic. They make up for this by getting extra dispell dice for free, and a variety of powerful anti-magic runes.
Dwarves are the strongest shooting army in the game, with rune enhanced warmachines and the most accurate handguns. Players looking to play a gunline list traditionally look to the dwarves. Often such pure shooting armies are frowned upon as being less fun to play for both parties, and on the dwarf end a gunline will quickly fold if your opponent does make it across the field. That being said, a strong shooting phase is vital to any Dwarf list. A dwarf army needs to drive the enemy into CC with their slower moving troops, or they run the risk of being run in circles all game.
Dwarfs offer a variety of elite CC troops to support their core warriors. Ironbreakers, slayers, hammerers, and miners all play very differently roles, and allow you to customize a CC based force.
Cheap flying machine:
Get your hands on one of the new plastic Defkoptas from the AoBR set. Whittle out the built in orc body, glue in a dwarf warrior. I tried to use some green stuff to give him goggles. Cut out the rockets and replace with something cylindrical for use as a steam gun, for example one of the big straws you get with boba tea.
Never ever buy the metal longbeards. Make a point of not paining any of your dwarf warriors beards white, then paint your whole longbeard unit with white beards. You can also make them look wealthier by comparison, giving the standard warriors more bronze trimming, and saving gold for the longbeards.
The dwarves are a fairly limited army, who basically do not participate in either the movement or magic phases of the game. In the shooting and CC phase though, they are one of the most varied and customizable armies, with both diverse troop types and runes to personalize units.
A Dwarf army runs the range from dirt cheap to one of the most expensive in the game. High point cost plastic core troops and warmachines maxed out with expensive runes can quickly take a low model count of plastics to the 1500 point and beyond. However as one looks to expand, the large variety of metals which should be fielded in large blocks get expensive fast.
For an in-depth discussion of Dwarves, see http://www.bugmansbrewer.com
Their toughness and reliability make dwarves a very forgiving army that's good for a beginner, yet they can expand into a strong and diverse CC force for a more experienced player. For those who enjoy showing up to the LGS with their beard and a case of beer, the dwarves are the only logical choice.