I fired mine up for the first time last weekend. I started early and kind of seasoned it. I got a costco pack of chicken thighs and a few pounds of bacon. I ran the chicken and bacon between 275 and 300 for a few hours, took them off, got the temperature down to 225-250, and put some ribs on. The bacon was toast but the chicken actually turned out good. We turned them into pulled chicken sandwiches. Ribs tasted good as well.
After assembling my unit and checking it over, there was little to no 'factory grease' or anything else on it. I just did the fatty stuff anyway, just in case, but like I said, the taste was fine.