I'm due for an upgrade from my iPhone 4. I've been considering upgrading to the iPhone 5, but am also interested with the Samsung Galaxy S4 because of its specs. However, I've been seeing some stuff concerning lag issues with the phone, and because I never had any issues with my iPhone, that makes me nervous. Does anyone have any experience with their S4 lagging or do they run relatively smoothly? I'm not 100% sure I'm willing to turn off things like animations (which is how I've seen people correct their problems on Youtube) because I feel like a quad-core phone should handle just fine.