Recently, I found out about the Trust Wallet for Ethereum. It is a Ethereum wallet designed for smart phones. It is very secure as private keys are stored locally, and the thing I love most about it is its usability.
I've just started using it and I must admit, it's the best Ethereum wallet for smart phones I've come across so far. You can browse all your ERC20 tokens with updated approx prices right from the app, and you can even access Ethereum DAPPs such as Crypto Kitties in the app.
You can read more about it here