I knew the 4.3-inch AMOLED display would be big, but I didn't realize how much screen real estate I would actually get. The Lumia 900's screen dwarfs that of the iPhone 4S, but the size of the phone still seems manageable. It is a tad heavier than the iPhone, but the good news is, with the edges fully protected in its polycarbonate plastic body, you won't be as paranoid about dropping the phone as you are with the iPhone.
And of course, powering that big screen will use up some battery life. I didn't experience any unnecessary battery drain, with the Lumia powering through a full day of use.