The features built into the UI and its functionality in general are important to me. Sony's UI's at launch are usually lacking, the PS3 didn't even let you access the dashboard without quitting the game. I want to see how parties work, the new share button, any new social features, sorting/grouping/folders, the new PS Store, friends list, etc. I don't know if it'll have much of an impact on my decision to buy one or not, but I want a good OS/UI experience on my new, premium console.