Aatrox is a fighter in Top lane who can heal way more than you can think.There are various champions that can do what he does better, but he is one of a kind.Don't be afraid when you have passive up and take advantage of the fact that people don't really know your abilities well.

The runes above are what I currently use on Aatrox and I think they are quite good.They are pretty much the same as old Warlord's but with much more Lifesteal

Pros:
1.Good amount of damage with his empowered W
2.Nice lifesteal with good sustain in lane
3.Players may not know his abilities
4.Variety of CC forms(knock up and slow)
5.More range with R

Cons:
1.Not good if he gets behind
2.Most champions can overpower him if they get fed
3.May die while in teamfights as he is the initiator
4.Tanks are a way to counter him

The best combo for Aatrox is

Q + E + R + W when Aatrox has more than 2/5 stacks of his passive

Aatrox is a champion that if mastered,can be turned in a beast.Use your combo effectively and guide your team to victory.