I have used Royal Oak, Big Green Egg, and Wicked Good lump, all with great results. The Wicked Good is awesome, but pricy when you throw in shipping. However, over the years I have learned to use briquettes with great results too, at a lower price. I have Kingsford Blue and Champ, Rancher, Royal Oak, and Stubbs in my stable of briquettes. Now that I have the WSM, I no longer see the need for lump. The Minion Method, along with the fantastic temp control, provides all I need for great smokes.
Hope this helps.