I need to choose now between xperia P and iPhone 4s?

A friend of me has two phones. An iPhone 4s 16GB with IOS 7.1.1. The iPhone is two years old but in perfect shape and it works correctly and has no damage. He also has a Sony Xperia P 16GB with android 4.1.2. The Xperia P is one year old and also in perfect shape. I want a phone for whatsapp. I want to be able to type fast on the keyboard. I also want to watch youtube videos on the phone preferable in HD. I listen to music, browsing the web, play some games, i don't want the phone to crash, i want to receive calls without trouble.(I heard some people about call receiving problems). So should I choose the Xperia P or the iPone 4s? And please give good reasons. I need to make a decision quite shortly.

Iphone has best apps and design, and has the best security by far. No virus checker needed, and you can install as much as you want without worrying about viruses. It also will not start lagging like other phones do.
Plus, when you resell it in the future, iphones hold their value far better then other phones, so you actually get alot more of your money back for it.