BlockChain  is good enough if you are using BlockChain online wallet.

bither(比太) also would be a good choice.

I don't have a specific recommendation but the wallet should have these features at a minimum
1. Only you can access the private keys, or it is a multi-sig wallet and only you have majority control.
2. You can back it up.
3. It is encrypted.

Online wallets are bad any way you spin it..

I've tried Circle, Coinbase, Blockchain, and a few other ios wallets.  I can't say that any of them completely blew me away.  There was always something about each one that bothered me. For the most part they all work the same, but the nicest feature on any of them that I really liked was that I can use my fingerprint on Coinbase.  It makes me feel like I am living in the future unlocking my account with my print. hahaha

I use blockchain  which has proved reasonably stable but I keep the coin count to a minimum given security issues

As far as security goes, I think breadwallet is the best, and it is the one I use. It's also the wallet with best design and usability.

If you have a Touch ID enabled iDevice, bitWallet seems like a good option, although it's a bit more hard to use (but nothing out of this world)