The Apple iPhone was the pioneer of high quality highly capacitive touch screens, screen which made their competitors look like sluggish snails. In fact even quite recently in a screen touch latency benchmark Apple's iPhones did quite well. Shockingly however, they failed miserably in this test.
Apple's iPhone 5s and 5c Fail Accuracy Benchmarks - Galaxy III Passes with Flying Colors
The benchmark was conducted by measuring the accuracy of the sensors. OptoFidelity had put smartphone touchscreens to a test by a robotic hand that basically poked the display and then compared what the phone actually registered. Interestingly, iPhones it turns out are more accurate in the bottom part of the screen - exactly where the keyboard is located, while in other parts of the display and even around the edges of the keyboard they are horrible. In fact they are so bad they don't register touch at all! Here are the benches:
However believe it or not Samsung Galaxy devices delivered an almost perfect accuracy register all over the touch screen. Giving what appeared to be an absolutely full coverage of the smart phone's touch screen. As you can see for yourself, while Apple's accuracy lies mostly in the center, Samsung's touch screens have brilliant coverage.
Herds another picture guiding users of the iPhone where exactly to be careful at (and to expect most typos). If you get a lot spelling mistakes near q, o and p then you can be damn sure that its not a co incidence, because that's where you will get the lowest accuracy on the screen. Granted sensors are small, but those buttons are not huge either.