Transportation to/from the airport is cheap both by bus express train and taxi. Terminal 2 seems like a low-cost terminal and waiting lines are usually long for those flying economy. And a lot of flights depart a bit late. But Terminal 3 is a piece of art. It's huge and from the inside it's really beautiful. As stated by P Smith it's also vastly underused which means I never had to wait was it for immigration security check or anything else. You have free power outlets for your laptop with free Wi-Fi like in Incheon for example but in my opinion with better natural lighting (although with no signs).