Android is quite popular than iPhone. Here's a reason:
Yup! Cheaper than iPhone. You get almost the same feature as iPhone. But if the phone getting cheaper means you get less features such as compass, GPS and more.
No need to owned more than 1 phone to use other SIM cards more than 1. Most of the latest smartphone (mostly Chinese branded, including Hwawei, OPPO, Lenovo, etc) have more than 1 SIM card slot. If you travel to neighbouring country such as Singapore and Thailand, you don't have to own 2 smartphones or remove SIM card and replace with country's local SIM.
Some smartphones (notably Vivo X5 Max and OPPO R5) are thinner than iPhone.
Customize home screen
Unlike iPhone, Android can customize the home screen such as add the clock, music play, previous and next button and other gadgets for your home screen. Most of newer smartphones don't have app buttons (except Samsung remains its UI including Android's own UI which used on cheaper smartphone.). Notably OPPO, Hwawei, Vivo and most China branded smartphone, including newer cheap and mid-end smartphone.
If iPhone, you need to press the home button 2 times to entered the recent app while Android press the left touch button (recent app button, mostly newer phone). For older Android phone, need to hold the home button to entered the recent app.
For iPhone, press the home button 2 times to entered the recent app and killed the app while Android only use the gadget called clean RAM button (something like a broom button on the screen). Press once and you will feel less lag than usual.