The iPhone 5s specifications and the Sony Xperia Z Ultra specifications are actually quite different. Both of these devices are meant for different uses and both do their job really well.
The iPhone 5s uses an A7 64 bit micro processor that Apple says helps the smartphone run faster than ever before. The Xperia Z Ultra uses a quad core processor rated at 2.2 GHz. While the iPhone 5s has a 4 inch screen the Xperia Z Ultra has a 6.44 inch display making it a much larger device – basically a phablet. The iPhone 5s has a 640 by 1130 resolution screen giving it 326 ppi while the Xperia Z Ultra has 1080 by 1920 resolution working out at 344 ppi, giving the Xperia Z Ultra a slight advantage.
A major difference is that the Xperia Z Ultra has expandable memory up to 64 GB while the iPhone 5s does not support memory expansion. While both devices have 8MP rear cameras; the iPhone 5s has a 1.2 MP front camera compared to the Xperia Z Ultra’s 2 MP front shooter.
The big difference comes down to usage. The iPhone 5s is very secure with the fingerprint sensor system in the home button while the Xperia Z Ultra has way more functionality thanks to its larger screen.