I wanted to investigate this topic because unlike before today there are many Android and IOS mobile application wallets such as, Breadwallet, Airbitz, Samourai Wallet and many more that allows to do crypto transactions claiming usability and effectiveness but when it comes to Bitcoin the main concern should be the safety than any other because its value and demand so,

1. What is the safest and usable Android Wallet do you suggest to store Bitcoin and to do transactions ?
2. Why do you think it is reliable  ?