Of all the armies I would recommend new players start with The Empire list.
The Empire is not truly great in any particular field (although it's strongest attributes are in ranged gunpowder weapons) but it is surely the most rounded adaptable army.
It can deploy capable hand to hand exponents to the tabletop and it has a good selection of special and rare units.
The character's, while not individually the strongest in the game, can be combined to great tactical effect when combined with the appropriate units and magical items.
Army stats are about average and they will rout no more or less than their opponents.
They can strike quickly or battle from distance and have some special machineries which can, at times, turn the tide of battle.
All in all, The Empire is a fine choice especially if you are not certain who you will be fighting next and you are not customising your army to take on a single regularly played opponent.
