Since i am using mytherewallet, i have no problems about it yet. For me, it's the best online wallet you can use for your Ethereum Request for Comment (ERC-20) tokens because it's coming from the smart contract blockchain of Ethereum too.
I like that too. besides using myetherwallet is an easy thing. other than that, it's also very simple. So far, I feel that Myetherwallet is a pretty good wallet for storing eth platform coins.