[Mobile] Saving - PlayerPrefs or Save?

I'm making a single player game on mobile (Android).

I was wondering whats the best way to save data on that platform (Android)?
PlayerPrefs?
XML?
JSON?
Binary?

I only need to store about less than 10 number values. (Current Level, Current EXP) not too much since it's just a mobile game.

I haven't learned anything besides PlayerPrefs yet, so it is worth it for the time-being to learn any of the saving types?

 

Personally I like PlayerPrefs on mobile because it's super easy to use. It's pretty easy to replace with some kind of cloud dictionary storage as well (e.g. iCloud on iOS).

Sam