The Galaxy S4's AMOLED screen has deeper, truer blacks but less pure-looking whites than the One's LCD display. The GS4's screen also suffers in sunlight: While the One's LCD panel remains perfectly viewable even in the most glary conditions, the Galaxy S4's AMOLED display is often difficult to see outdoors and practically useless in direct sun.
One area where the Galaxy S4's screen really shines is in pressure sensitivity: The phone has a somewhat hidden "high-touch sensitivity mode" that -- if you can manage to find it -- will allow you to use the device's touchscreen with gloves on. I tested it using medium-thickness winter gloves and found it worked fairly well; the screen's responsiveness was a bit hit and miss, but considering most smartphones won't recognize glove-covered input at all, the capability will be a welcome addition for anyone in a cold climate.
The button factor
System navigation buttons are a key part of the Android experience -- and while Google moved to a virtual, on-screen approach for such functions with its Android 4.0 release in 2011, Samsung continues to stick with a dated and rather peculiar hybrid button configuration on the Galaxy S4.
For folks who are used to Samsung devices, the phone's physical Home button flanked by capacitive Menu and Back keys won't be much of a shock. But compared to the native Android experience, the setup presents some significant disadvantages.
The first relates to Samsung's decision to include the Menu button -- an element Google removed from the platform at the start of the 4.0 era. The old-style Menu button was eliminated for a specific reason: On button-free devices, a special onscreen icon signals the presence of functions related to the OS or to specific applications -- functions like accessing advanced settings in Gmail, requesting a desktop version of a website in Chrome, or viewing your list of installed apps in the Play Store. In Samsung's setup, there's nothing to let you know when those options are available unless you think to tap the Menu button at the right time.
Samsung's setup causes some core system functions to be similarly hidden, like the app switching tool -- a useful utility that lets you jump directly from one application to another. In devices that follow Google's design recommendations, that tool is accessible via a persistent on-screen icon; on the Galaxy S4, you have to long-press the physical Home button to find it -- an action that won't be obvious to most users.